Box in a Bag Shipping: What You Need to Know

Putting your box in a bag is a "cheat code" that sometimes lets you save even more money when shipping USPS Priority Mail Cubic
Box in a Bag
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If you’ve spent any time on our site (or on online shipping software in general), you likely know that shipping USPS Priority Mail Cubic is the best way to save money when shipping packages. However, what if we told you there was a way in which you could save even more? Well, by placing your box inside a poly mailer or envelope, you might be able to! This is a special trick known as the “box in a bag” shipping method. Lots of eCommerce shippers use this method every day to cut down their shipping costs, because when you’re shipping tons of packages, every cent counts!

What Do You Mean, Box in a Bag?

The “box in a bag” shipping method is pretty much exactly how it sounds. All you need to do is place your box inside a poly mailer, or a shipping bag. Seal the bag, buy your postage, send it off, and call me Captain Obvious!

Keep in mind that you’ll only be able to take advantage of this “cheat code” when you use online shipping software to buy discounted USPS postage online.

How Shipping Your Box in a Bag Can Save You Even More Money

We wish we had a better explanation here than “That’s just the way it is”…but this phenomenon of saving money by shipping your box in a bag is just how the math works out sometimes. Hey, we don’t make the rules! We just know how to tip the scales in our favor.

Believe it or not, shipping a box in a bag applies beyond just Priority Mail Cubic. In fact, a lot of shippers utilize the box in a bag method when sending lightweight items in smaller boxes via USPS First Class Package Service. Some examples of these kinds of parcels include shipping perfumes and fragrances.

What Cubic Pricing Tier Does My Box in a Bag Fall Into?

To calculate your cubic pricing tier, simply measure the Length and Width of your envelope in inches before you put your box inside of the bag. That last part is important! USPS technically only cares about the dimensions of the empty envelope, so don’t worry about putting box inside of your bag when measuring your dimensions. If either dimension exceeds the nearest quarter inch, round down to the nearest 1/4 inch (for example, 7.8″ inches turns into 7.75″ inches).

Once you’ve got the length and width of your bag, add those together to calculate your cubic pricing tier:

  • 0.1 – Envelopes with a Length plus Width measuring more than 0″ up to 21″
  • 0.2 – Envelopes with a Length plus Width measuring more than 21″ up to 27″
  • 0.3 – Envelopes with a Length plus Width measuring more than 27″ up to 31
  • 0.4 – Envelopes with a Length plus Width measuring more than 31″ up to 34″
  • 0.5 – Envelopes with a Length plus Width measuring more than 34″ up to 36″

Next, once you’ve got the pricing tier that your bag belongs to, check the table below to see how much it’ll cost to ship!

Pay Attention to the Restrictions

As always, you need to be aware of certain restrictions when it comes to shipping your box in a bag. We’ve listed those out for you below.

First and foremost, neither your bag’s length or width can exceed 18″ in either direction. Also, just like regular Priority Mail Cubic, your bag’s total weight cannot exceed 20 pounds (lbs).

Last but certainly not least, you need to make sure you’re using the right kind of envelope or poly mailer. USPS will not allow you to ship the “box in a bag” method with expandable envelopes. You know the type—they’re the ones with the crease in the middle that compresses down and up to create more space inside the bag. Here’s a picture, to show you the kind of envelope we’re talking about:

Expandable Envelope

These kinds of envelopes are a no-go! If you’re using an expanding envelope like the one pictured above, USPS will treat it as a 3-dimensional box. As a result, they will charge you accordingly via their Automated Package Verification System (APV)…and no one wants that to happen.

Can I Use Any Kind of Bag? A Trash Bag Perhaps?

A lot of people wonder if they can use a trash bag to ship their box in a bag. The truth is, there’s a little bit of grey area here. USPS technically won’t restrict you from using a trash bag, but here’s what it comes down to: whatever kind of bag you use, you need to make sure it doesn’t “form fit” to the box. By “form fit,” we mean don’t tape the bag too tightly around the box. If the bag form fits to the box, then it will make the package look like a box. If it looks like a box and is shaped like a box, USPS will charge you for shipping a box. You catch our drift?

Have any questions about saving money by shipping your box in a bag? Leave a comment below!

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68 Comments

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  1. Fred D.

    What about internationally? The cheapest I can find to ship something to the UK, for example, is around $17.85! I want to ship circuit boards that weigh under an ounce. So let’s say 3 ounces for a 5×7 bubble pack and some thin styrofoam to protect the pins. Can I consider than regular mail somehow? I know I could if it was “correspondence only”, but it is obviously not just paper. And what about customs forms and VAT? I was hoping if it was a “gift” and under a certain value, the paperwork and any other chargers would be minimal.

    Reply  
  2. DeeM

    I am starting a new business and have to mail a light product in a bag (It is not boxed). The product weight is less than a pound. The product will fit snugly into a 7.5 * 8.5 bubble mailer. ( It needs protection as it is not boxed). Any pointers or advice from the mailing gurus for the cheapest mailing option for this. Should I use a larger envelope for a looser fit ? ( Looser fit may also mean less protection). Greatly appreciate any input. This is a low cost product and looks like shipping costs is more than the product itself.

    Reply  
    • Bunnie White

      Hi DeeM. The poly bag option is great when you have something really heavy or something light and fluffy that doesn’t need a box. The item you are shipping actually needs protection, a box. That box can be slid into poly but at your weight/destination there may be a cheaper option. There are postal materials that are free for you to use in business. If you find the item you are shipping can fit within those postal boxes that could be your saving grace. FREE hardy boxes. But all those materials ship as they are labeled. Priority Mail, Flat rate, Regional Rate, etc. You COULD theoretically put that box in a poly bag and instead of shipping 3 sided measurement you ship by only providing 2 measurement of the poly bag. Again the corners of the poly bag must be relaxed, not deformed by stretching. In your case 12 by 10 poly bag to fit your 7.5 by 8.5 item would be about right (you didn’t provide the thickness so that is just a guess).
      Also anyone using shipping for business would be amiss if they failed to point out to you regional rate options with the USPS. Regional rates have 4 different sized boxes. To ship regional rate you MUST use those boxes only (No poly bag covering). Regional rate boxes can be ordered for free from the USPS website as well as the flat rate small boxes. Look at those sizes and see if you can use any of those free boxes. Back to regional rate. Regional rate provides you a cheaper means to ship based on the rate beginning with where you are located…and you pay ONLY for the distance it travels from you. Conversely, flat rate is ONE RATE FORE EVERYONE coast to coast etc. no matter your distance to the destination. Flat rate MUST use those materials and flat is best for heavy items. I just used a regional rate RATE to ship a state away that was $2 dollars cheaper for me, than flat rate AND the poly bag option. My advise is to get quiet, focus, and study until you comprehend the options served to you on the drop down here on Pirate Ship. There in the drop down box you are served all options. I find myself tweaking a size or weight and look at all choices until I choose the right one. Point is there is NO ONE ANSWER TO COVER THE RIGHT CHOICE EVERYTIME. OH, if you don’t already own one, get a postal scale or a kitchen scale. I got mine at Walmart in the kitchen area. Glass top battery operated. Weigh all intervals as you package. Decide what is absolutely necessary to ensure the item arrives in good condition. Often removing one tuff of tissue will keep you at the lower price rate. Or play with one box shape to another. When I first saw your plea, my first thought was a free flat rate box slid into a poly. But the small flat rate is 8 by 5. The size of a VHS tape. Not knowing your destination it would be hard to provide you a definitive solution. Again if your buyer is in your state, or a state away, regional or parcel post would be the cheapest. If you are an ebay seller, ebay ups first class weight to 16 ounces while the postal counter is 12 ounces. Also you can ship your item in a PLAIN brown box, (not free postal material) and ship it parcel post. Any postal printed box must ship according to the label printed on it. What is the thickness of your item? Can it be rolled into a tube? Let me know if anything needs clarity. My rambling may not be applicable to your question. Describe the shape by telling me a comparable item. Book or pineapple? : )

      Reply  
      • DeeM

        Thank you sooo much, Bunnie White. Wealth of information. My product is only 2 inches tall. The packaging currently is a drawstring bag. I am thinking I would just use a bubble envelope. It is plastic and I think that is the only protection it would need. However even 2 inch doesn’t qualify it for an envelope..when i take it to the Post Office, they treat it as a package. I will try the free flat rate box for VHS and see if this fits into it too. Thanks again, Bunnie.

        Reply  
    • Courtney Ct

      You can make your own box, reuse boxes, and then put in envelope like poly mailer or flat rate envelope to ship. Clothing put in clear bag with suffocation label (if opening of clear bag is 5” or more) then put sealed clear bag in poly mailer to ship. Small boxes (4x3x2) can be bought on average for $0.22 each. And put into a bubble mailer no worries. Or just mailed by itself since it doesn’t cost much to ship small packages under 6”. Feel free to email me. I’ve been selling on e-commerce since 2015 and have learned a few things over the years to help with shipping costs. Also side tip. I have a lot of shipping supplies for free from friends, family, clients and neighbors who bring me their saved packaging supplies. That will help you save money too.

      Reply  
    • Jonathan

      Box in a bag has potential. However, when I buy an item, i.e computer parts they are sensitive to shock. Do you really think you’re saving money by shipping in a bag?
      If the box and/or part is damaged, it will be returned at your expense. How much money do you think your saving now?

      Any sensitive items that I buy in the future, if it will be automatically returns until it is delivered in a secure box. It’s time for America to stop being so cheap.

      Reply  
      • Bunnie White

        Jonathan, that secure box you ship in…isn’t handled like nitro glycerin. It is going to be flipped, tossed, stacked upside down and down side up. All we are saying is if your box is small enough (under 17.5 inch by 17.5 inches) put your box in a poly bag for a cheaper rate. The SAME exact box you already packaged your delicate contents in cloaked in a poly bag is going to save you on shipping fees. ALL major retailers are doing it, why not you too? Hope that helps friend!

        Reply  
  3. danasmc

    So I’ve been using medium (12×12) usps priority boxes and wrapping them in black plastic. Is this a no-no? So far, thank the good Lord, I’ve not received any correspondence from the postal service. I’ve been doing this for about 5-6 months.

    Reply  
    • Courtney Ct

      That is a no-no. The bags must be usps approved. Polymailers are best way to go. Poly mailers can be as low as $0.01 -$0.03each if you can buy master cases, which come in boxes of 3,000-5,000 bags per box. Otherwise next cheapest is to buy them by 1000 piece cases at a time. USPS has the bag approved rules in place because packages can get damaged on their conveyor belt systems. And if the bag gets stuck on conveyor and rips or falls off, the item inside has no label to help them determine who’s package it was or where it goes, at which point the item has a high probability of getting sent to a lost and found USPS Warehouse. Item sits at this warehouse for up to year and if sender or receiver can’t be found USPS then auctions the item for profit. The USPS approved poly bags are rip, tear, and water resistant which means they are more likely to make it through the shipping process the safest without damage.

      Reply  
  4. Brad

    Any idea what size poly mailer will fit a 1097, 1092, a 1095?

    Reply  
  5. quack

    hi for example i’m putting a large flat rate box in a 14 x 19 poly bag. so i’ll put 14 x 19 on the pirateship entries? ive been seing people enclose their bags like a box which makes it cheaper. which is better?

    Reply  
    • Bunnie White

      NO Quak. The max is 18″ by 18″. If your actual item is 19″ you are TOO large to use poly. When you say LARGE FLAT RATE does your box measure 12-1/4″ x 12-1/4″ x 6″ ? Does your item HAVE to be contained in that box? Can you cut it down? I have often used the postal materials, but custom fit the item to a snug fit in the box simply by recutting and scoring just as the box design is, but make the cut inset to the size of my item. If I am visualizing your package dim correctly, I hate to tell you you are too large for the poly in the bag cheap option. Also, did you know you can edit the size of the poly bag by cutting it down or taping it back. For example you can use a 20 ” square poly bag and just fold it back and cut it down to 10″ etc. The smaller the poly bag measurement, the least expensive your rate will be. I often tweak it to get the rate down to the lower rate. THE KEY TO POLY is again: DO NOT PERMIT THE BOX INSIDE TO BE apparent a box. You can NOT wrap poly around a box and benefit from the cubic rate. It must appear like a bag. Not a box in a bag. Your large measurements will stretch that poly and it will clearly be evident you have stuffed a box in a poly bag. NOT ACCEPTIBLE. Oh, one more thing 18″ is max so always strive to maintain 17″ corner to corner max. Again, a relaxed bag corner is what you need to achieve. If there is anything not clear in this comment, write back. I am currently available.

      Reply  
  6. Kelly L.

    This just completely blew my mind. I’ve been shipping things for a while, usually clothes in the bubble mailers, but I had a box to ship today and have just recently started using Pirate Ship instead of PayPal shipping, and out of curiosity I looked into the “box in a bag” option so I had to google “WHY?!” and landed here. This is fascinating and even the other comments have been helpful on tips for shipping. It may only save a bit under $2 in this case, but that’s definitely going to add up over time. Going to go buy a bunch of poly mailers now! Thank you all!

    Reply  
    • Bunnie

      YIPPEE! Trust me it will add up big time when your weight increases on your item! Poly bags are on the shelf at Walmart. Dollar tree has them singularly and I feel are cheaper why to get a variety of sizes. Amazon and office supply I find are moderate in price. Remember the next item YOU receive in a poly is a reusable poly! Cut it open carefully and retape the cut for your use. A tip I learned is NEVER enter 18″ in the size. That is the max. Even if you poly is 18″ use 17.50 as your size. 18 will not be accepted. Glad you see the light, from the pirate’s lantern! Be well.

      Reply  
  7. JoAnn

    Can I ship using the box in bag option, with another carrier other than the USPS? I am shipping with PIRATE SHIP online shipping service, and when I put in the information for boxing bag, UPS also comes up as an option. This is confusing to me.
    Also, I am chatting with Customer Service on pirate ship and she is telling me that my 16 x 12 x 10 box, cannot be put in a bag! She said it might run into problems. I don’t know why that is because it is under 10 pounds and under 18 inches. How can I get a definitive answer about both of my questions. I would appreciate help so much.

    Reply  
    • Bunnie

      JoAnn, your box of 16 by 12 by 10 would require you to WRAP THE BOX IN THE BAG. The maximum width is 18″ even though one of your measurements IS under 18 your others STRETCH that poly beyond what is legal. For the sake of discussion, your box at 16″ would have to be only 1 inch thick to slid into a poly. BUT that is only one side of the box. The other would ALSO require 1 inch. So now your 16″ box is 18″ which exceeds your size allotment. I hate to tell you, but on this size box THE POLY BAG IS NOT AN OPTION FOR YOU. No other carrier will accept it. 18 is the max so technically you need to come to 17.50 in the future. I always check the rates on all 3 majors. Online is going to be cheaper and having an account with all will always help you on rates. But this time you box is TOO LARGE for a poly. Sorry. Have you over stuffed the contents? Is there anyway you can choose a smaller box? Regional rates postal allow you to pay only for the distance it travels. Flat rate postal is coast to coast no matter the shippers location. Regional rate boxes are usually only available via mail order. Go to USPS and look up the measurements for REGIONAL rate box A and B and see if you can fit your item in either. Flat rate postal are predetermined box sizes as well. Meaning you can’t ship in your toaster box flat rate, you must use USPS material. Pirate offers these rates. I ALWAYS buy my label from them even if it is the same at USPS. I want to support pirate to keep them strong for the times I need the poly option. Again, this is not a poly bag time for you…I realize that is hard to hear. But the pirate on the phone was correct. Best wishes, hope this helped.

      Reply  
    • Bunnie

      Shot in the dark here…JoAnn, does your Item in the box HAVE to be in a box? Can you wrap it in bubble wrap and decrease the measurement/size of it? sometimes we get all boggled up thinking it has to ship in a box. It DOES NOT. I had impact wrenches (tool think of an electric drill). they weighed 9 lbs. I took bubble wrap and encased them COMPLETELY. they looked like a butter ball turkey. Put that in a poly and used 17 by 17. I was able to ship that HUGE butterball for $9.00 with Pirate Ship Cubic Rate Poly Bag option. (there is a drop down box in the method of choice, you MUST choose bag, envelope etc. to obtain poly rates). Anyway, I wanted to make sure you knew, the poly bag may STILL be an option if you can bubble wrap what ever you have placed in the box. Keep that in mind, if not for this application, but for the next. Hope that helped.

      Reply  
      • JoAnn

        Thank you, All, for answering my questions. Somebody said that I had to “wrap the box in the bag” which is exactly what everybody I know in my group does. They literally wrap the box in the bag, not loose like I’m here? Hundreds of packages have been shipped like that with no problem.

        Reply  
        • Bunnie

          When you say WRAP THE BOX in the bag…do not WRAP it like a gift. Meaning, do NOT conform the poly bag to the 6 sides of the box. That is simply applying plastic covering to a box. THAT IS NOT WHAT BOX IN POLY BAG IS ALL ABOUT. When you take a box and ship it, you use 3 dimensions. Those three dimensions plus your weight is what you package price is based on. The beauty of the poly bag is it erases one of the three dimensions you must use in shipping a box. The key here is the four corners of the poly bag MUST not be stretched or mis shaped. They need to look just like A corner looks on a piece of writing paper. WHY you ask? If JUST four corners are visible those four corners make up 2 dimensions. Length and width. For example an 8 by 10″ piece of paper only has two dimensions. In this magic pixie dust world of cubic rate, that 4 cornered poly bag TRUMPS or erases the 6 cornered box contained within…AS LONG AS THE FOUR CORNERS are in tact. IF you wrap a box in poly, you have defeated the entire point. Do not wrap the box like you would a Christmas gift. Put the box in a bag and make sure the four corners of the bag relax enough to be four corners. I hope this helps you. PS. Get an 18″ by 18″ poly bag and for a lesson put a ring box in, then a box of cereal then a shoe box. Eventually you will see as your box inside enlarges that 18″ poly bag gets smaller and smaller. Eventually your enlarged box you slide inside will no longer allow the corners of the poly to be recognized. THAT IS THE LIMIT. You can no longer use poly. For anyone else following this, I always edit my poly bag size in relation to the contents within. That ring box can go in 5″ by 5″ poly for example. HOPE THIS HELPS. I am outta here!

          Reply  
  8. Concerned Customer

    Lately, I’ve received a lot of damaged or leaked items from “box in a bag” shipments. The result is a missed sale and a dissatisfied customer, since these items must be returned because of damage. Polymailers are great for the intended use ( such as folded clothing); but for gift items that need to have the product packaging intact; or liquids and cosmetics that often leak during shipping, it’s not such a good idea.

    Reply  
    • Bunnie

      There still needs to be MINDFUL conscientious method at packaging. Shippers still need to make sure the contents won’t be damaged. I continue to use my Impact Wrench as an example. It weighed 9 lbs. But wouldn’t not fit in any 9 dollar flat rate option with the post office. This thing was CAST metal, heavy and strong sharpened edges. I took that wrench and taped large bubble bubble wrap on every edge. Nothing was exposed. Taped it with shipping tape. Then took that “BUTTER BALL Turkey” shape and slid it into a poly bag. Had it hit the floor the amount of bubble it would have bounced. The shipping cost: $9. As a recepient: I received a number 10 can of long term food storage product in a poly bag. It was JUST placed in the poly. No protection. Not in a box. The can edge arrived dented/can opener will not work to open it. The poly bag was in tact. That shipper failed to do due diligence prior to shipping. A fluffy sweater arrived in a lightweight bag in a poly perfectly fine. The key here is the bag is not a silver bullet. It is not kevlar, it is still the shippers responsibility to protect the contents well. It is not the bag that failed you here, it is the shipper not comprehending the need to protect the contents. Box it, wrap it in sheet foam, or bubble wrap, tape cardboard around things that may collapse. The bag is a tool that enables you to lessen your shipping costs by the use of 2 dimensions. It does not replace logic. PUT GLASS IN A BOX with padding and peanuts just as you would do normally, then put that box in an oversized poly and pay less than you would for the box.

      Reply  
  9. Where does one buy these polymailers & are they plain or printed

    Reply  
    • Rockwell Sands

      Hi Sandra – you can buy these poly mailers at either ULINE or Amazon! I personally use these plain ones that are 13×10″ from Amazon.

      Here’s a link to some on the ULINE website too: https://www.uline.com/Grp_191/Poly-Mailers. You can find any size and color you want there!

      Reply  
    • Bunnie

      Hi Sandra, if you are in need of it quickly WMT retailer have poly on the shelf in several sizes. Also dollar tree offers several options including a bubble lined poly. ANY poly bag you have received in a shipment to you, is reusable provided you can make the corners return to their original shape. I open all my poly’s with care with deliberate intention to reuse (and retape as the original seal is not salvageable). Remember the sweet spot to make poly worth your while is if the item fits and the “pointy pillow corners” of the poly are not stretched or misshaped. They must appear just as they do unfilled when you first buy the poly (do not wrap an item in poly like a gift or present). Loose fitting. Once that corner is no longer visible you have defeated the cubic rate grace allowance and you got back to 3 dimension equation UPCHARGE to your account. It may happen up to 5 weeks after your delivery!!! Or package returned to you. Don’t proceed unless you comprehend. Pirate cs will accept a photo of your package to assist you if you doubt yourself. I had to several times, until it clicked. Be well.

      Reply  
  10. gina d karaba

    hi I found that I want to ship a box inside a bag simply so the small package doesn’t get lost. But I’m curious how big a box I can out inside. I also never get the option to put only 2 dimensions in. I’ve just shipped a 5 x 5 x 5 box inside a bag but I had to pay MORE to put it in the bag because it weighed more. ?

    Reply  
    • Rockwell Sands

      Hi Gina – there’s no real answer for the maximum size of the box you can put in…but the maximum size envelope you can use to qualify is 18×18″. When entering your info, you’ll need to select “Envelope or Poly Mailer” instead of a box, that way you’ll have the option to only input two dimensions (and these will be the dimensions of your outside envelope). I hope this makes sense!

      Reply  
    • Bunnie

      If you are on Pirate IT IS UP TO YOU TO CHOOSE the method of package!! They assume it is a box. So your job is to tell the form you are using a poly bag. On the page where you see RIGID BOX at the top, click the arrow pointing down on the right side. That click will open a lot of options. Once opened click on: Envelope, Padded Envelope, Poly Bag, Soft Pack, or Box in a Bag. From there you enter the POLY BOX dimensions which only allow 2 numbers! note: Max is 18″ by 18″ so you must enter under that measurement. You can still use an 18″ by 18″ poly, but enter the dim as 17.50 by 17.50 or less depending on your contents. Your example of 5″ cube would fit using a much smaller dim making sure the pointy corners of the poly are noticeable not formed to your 5″ cube.. Hope that helps!

      Reply  
      • JoAnn

        I was chatting with someone on pirate ship and they sent me a link about using box in bag shipping. . I’ll paste the link at the bottom of this question. The directions given, say to measure the length and the width of THE BOX, then , add them together and Look on the table given, to see which category it fall into. My box fell into category 0.4..

        So those directions don’t say anything about measuring the bag. As a matter fact it specifically says to MEASURE the box BEFORE putting in the bag! .
        That’s why I’m confused, because there’s a lot of conflicting instruction.

        My other question is how do I know how many miles are customers from me. Is that automatically calculated when I put the customers address in? I’m assuming so.

        https://www.shippingschool.com/box-in-a-bag-shipping-what-you-need-to-know/

        Reply  
        • Rockwell Sands

          Hi JoAnn – sorry for the confusion! You definitely want to measure the dimensions of the bag, and not the box, for this method. I’ve cleared up the language in the article to reflect that. As for how many miles your package is traveling, when you plug in your package info to the Rate calculator on Pirate Ship (if you’re still using Pirate Ship, that is), it will tell you the USPS Zone your package is traveling to. USPS Zones measure distance, not areas, so this will give you an idea. I hope this helps!

          Reply  
          • JoAnn

            But I entered my measurements in pirate ship which were 16 x 12 x 10. I got the box ready. Then I went back and switch to box and back to see what the savings would be. It automatically took the 16 and a 12 and put that in for the measurements, using boxing bag. What came up when I pressed get rates, were options from UPS and United States post office. He was a savings are about four dollars. I’m just so confused. Only US PS is mentioned for the boxing bag option, but can I do it for UPS as well?

        • Bunnie

          Yes, I agree with Rockwell. I always understood the measurement to be of the bag. You can put a ring box that is 2inch square cube into a bag. The ring box is now no longer part of the equation. Your bag (for example) random size lets say it is 8 inch by 6 inch trumps the ring box. The kids game rock scissors paper, the poly bag trumps the contents. The key that everyone needs to grasp is DO NOT FORM FIT the poly bag to the box contained within. In this case the 2 inch ring box. Let that ring box flop around and bounce around in the poly. Or stuff a fluffy sweater into the poly bag. Or a shoe box. Or a foot ball. Always allow the poly bag enough space on all sides of the contents that the natural corners/seams of the bag are relaxed and not stretched out of shape. My first poly I couldn’t wrap my mind around the idea. But eventually it clicked and I finally see the light. Can’t think Pirate Ship enough. REALLY saved my bottom line on ebay sales numerous times. Poly Bag Cubic Rate rocks!

          Reply  
  11. Shanandoah McQueen

    So why not just put the product in the bag and leave the box out? Wouldn’t that be even more cost-effective?

    Reply  
    • Bunnie

      The main thing here is the grace of 20 lb weight limit and the allowance to only pay for a thin package material covering of a poly bag and not a 3 sided measure box. The limitations of an economical rate in the flat category was your only option with out cubic, and flat rate must fit in those specific sized boxes. The poly bag offers an option for that gap. Also some things shape or weight would be difficult to maneuver if not confined in a box, in the bag. Somethings need the rigidity and protection of a box to arrive in the proper shape in which you expect. Somethings have a sharp edge that may break through the poly bag. If you can bubble wrap a shape and protect it with padding then by all means just use the poly. If you are shipping a teddy bear stuff it in a poly bag. If you are shipping a ceramic bear, bubble wrap and pad it, place it in a box then put that in a poly-but allow the poly corners to be seen, not stretched over the box as in wrapping a gift. Hope that helps.

      Reply  
      • Sabina Charles

        I was VERY surprised to see that this method was suggested for perfumes. According to USPS the ONLY way fragrances can be sent is Ground shipping as they are considered hazardous material and if not sent ground it is subject to fines.

        Reply  
        • Courtney Ct

          Shipping perfume is only allowed if it’s a spray and not something that must come into contact with skin for application otherwise it’s considered cross contamination and not allowed to be sold online unless it’s stated as selling it for antique, vintage collectors. Also USPS will require that on perfume bottles that still contain perfume you must write on side of box immediately to the side of box that label is posted, the words “Consumer Commodity (first line), then underneath ORM-D (for second line), then Ground Only (for third line). This will ensure you are disclosing to them the perfume inside the box in case it doesn’t show on the label. So you won’t be liable if something happens during shipping. Hope this helps.

          Reply  
        • Lisa Fletcher White

          When you ship be mindful there will be NUMEROUS hands and machines that touch your package. If I was sending a bottle of ketchup, motor oil or fragrance it would be prepared like nitro glycerin. First put in a durable sealed bag perhaps two layers of zip loc. Then Bubble wrap the bottle like a butter ball turkey. Put that turkey in side a box with foam peanuts. Make sure the box is at least single wall corrugated, meaning don’t use the box your corn flake cereal came in. THEN I would have no apprehensions about sending my bottle of any fluid. If I had done all those steps and still fit into a poly bag, I would SHIP IT. The poly bag at this point of my explanation is simply the covering. It is NOT the protection. If anyone say to poly bag glass, they didn’t intend for the bottle of perfume, ketchup or motor oil simply to be put in poly. Hope that cleared that up for you. -rules must be stated for the persons who would ship irresponsibly. Don’t be one of them. Treat everything you ship as if it is your only child. : )

          Reply  
    • Rockwell Sands

      You could do this! But a lot of shipments only get sent in cardboard boxes, like in the case of subscription boxes or fragile items that need protection. The “box in a bag” method if mostly for shippers who need to send their packages in boxes to try and save even more money by putting their packages inside of poly mailers. Hope this helps!

      Reply  
  12. Bunnie

    Eureka! I just got it! I couldn’t wrap my mind around why the poly bag lowered my rate so substantially, when my weight remained the same. I think I may be able to help clear up the box in a bag fog.
    So the reason this cubic rate is SO attractive is it takes only TWO dimensions of your “POUCH” shaped package. Length and width. (think of a pillow). Conversely the measurement for a box takes THREE dimensions. Length width and height. So…In order for your package to qualify for the pouch (cubic) rate, and not the box rate, it must Look like a pouch. It has to convey it is pouch. Ask yourself from across the room do you see a pouch or a box? If YOU SEE a box, then the PO will see a box. And very likely while handling it, they will up charge you for THREE dims!
    What the pirates are trying to get across is A, you can’t wrap your box like a birthday gift. (that will look like a box). B. You can’t shove a box in a poly and have it stretched to capacity (that will also look like a box)
    If you are putting a box in a poly mailer, be sure the bag is oversized enough, or loose and extends beyond the boundary of the recognizable shaped box contained within. The poly bag purpose is to DELETE the 3rh dim measurement of the box and look like a stuffed pillow. Again from across the room do you see a pouch? Or a six sided box? If you see a box they may re measure your box which will add that 3rd dimension and tag your account for the full counter priced rate.
    If you don’t have enough loose poly bag under 18″ max on either side (of a box), cubic rate is not for you. AND…if your item doesn’t need to be in a box, YOU ARE GOLDEN. SHIP the football, rain boot, teddy bear in a poly bag…it has no sides once in a bag with 2 dimensions!!! Hope that helped!

    Reply  
  13. Kris

    Does anyone know where I can find this in the Domestic Mail Manual DMM?

    Reply  
  14. Kris

    Had a man come into our post office last night. The clerk he went to noticed he had cubic rate prices on his packages but they were only 2 dimensional. She thought this was odd because cubic is usually more than 2 dimensions. The man said that because they were bagged they fell under the box in a bag cubic pricing which only requires the lengh and the width. He said he bought these bags specifically for this method of shipping. The problem I saw was that he had taped the bags so that they form fitted the box. I did not know at the time about box in a bag cubic shipping but to me they looked like wrapped (not bagged boxes). The clerk that was helping him explaned that his accout would be charged if the system found any problems between his shipping label and packaging method. He said that he had been shipping them that way for years and not had a problem. The clerk let him know that he had just been lucky. He got upset and said he would just take his packages to another post office were it won’t be a problem. I’m sure if he checks whatever account he pays his shipping with he will probably see some extra shipping charges. Maybe not for all but for some. Whatever you do don’t defraud the usps because it will eventually catch up with you and it could result in felony charges depending on the amount at the very least a big hassle with the postal inspection service which is a federal law enforcement agency. Thanks for the info on this page I am going to share it at our post oftice so we know what box in a bag cubic pricing is and how it works.

    Reply  
  15. Custom Design Boxes

    Outstanding.. your outlook on this is amazing

    Reply  
  16. Joan Recker

    How do you calculate shipping charge on a poly bag?

    Reply  
    • Rockwell Sands

      Hi Joan – the cost to ship depends on the weight of your bag, its dimensions, and how far away you’re sending it. I usually use a simple rate calculator to see how much a package will cost to ship. Here’s one that I use all the time that you can check out: http://www.pirateship.com/rates. Just type in all the info for your bag, and it’ll show you the cheapest way to ship it!

      Reply  
  17. Tee

    Hi there. I need some advice. I’d like to ship my orders in 9x6x4 inch LWH. Can you recommend a msg for me? Thanks in advance😊

    Reply  
  18. Robin

    Hi, when I put the dimensions of 18″ x 18″ poly mailer in Pirate Ship Box in a Bag setting, the price page shows the regular Priorty Mail rate instead of the Cubic Rate and doesn’t give the option to even see the price of the Cubic Rate for an 18″ x 18″ mailer. If I change the parameters to 18″ x 16″ for instance, it will give the cubic rate price. Do you know why that would be? Thanks.

    Reply  
    • Rockwell Sands

      Hi Robin – I think that’s because you might be at the maximum dimensions there, for cubic Box in a Bag. The max dimensions is 36″ inches in total (length + width), so you’re coming up right on that threshold…and regular Priority Mail may actually be cheaper. Have you tried buying the label with a smaller dimension, like 17.5 x 17.5″? That may help you lock in the cubic rate! Hope this helps.

      Reply  
  19. Nancy

    So, can you use a brown grocery bag, put the box in, then just seal the end of the paper bag?

    Reply  
    • Rockwell Sands

      Technically, yes! Just as long as it doesn’t clearly look like a box inside of the bag.

      Reply  
      • Jack

        Please, please, please use a grocery bag. The more people that ship incompetently makes me look better as a seller. Send it off in a grocery bag and make me more money.

        Reply  
    • Gladys Marie Snyder

      No you can’t use a grocery bag because it is gusseted (expandable)….it has to be a flat bag, not one you fold out to make bigger.

      Reply  
  20. Mary Prola

    So for those of you that think it is ok to use a FLAT RATE USPS box inside a bag to save $ it is not. It is a violation of USPS regulations-so be aware

    Reply  
  21. Dan

    Can you use a USPS priority mail box as the inner box since it’s still going USPS Priority Mail? If so is a flat-rate box also acceptable?

    Reply  
    • Rockwell Sands

      Hi Dan, as long as the box is concealed by the bag outside of it, you can use any box you like! Just make sure it doesn’t look like a box, and that the bag doesn’t “form fit” to the outside of it.

      Reply  
  22. Travis

    Is there a spot in eBay like there is in pirate ship to select bag instead of box?

    Reply  
    • Rockwell Sands

      I’m not sure Travis! I believe you can pre-select your packaging and choose envelopes or mailers instead of boxes…that would seem like it makes the most sense 🙂

      Reply  
    • VICTORIA MARGARET

      Travis, you don’t have to ship thru ebay… even though it’s easy… just use pirate ship 🙂

      Reply  
    • Heather Tankersley

      I am not sure about ebay. But Etsy doesnt have this feature. So i use pirate ship to ship my Etsy orders…only the ones i can do box in a bag. Again, Etsy doesnt have that option.

      Reply  
  23. Sammy

    Do you measure the length with the top flap open or closed Thanks

    Reply  
  24. Ahlora

    Thank you for clarifying this!

    Reply  
  25. Yogi

    Hi. I am confused. I thought I had the rules figured out until the last part where you talk about trash bags. Where you speak about the trash bag at the end, are you hinting that if you do have a bag or trash bag that is longer than 18 inches in any dimensions, that that is acceptable?

    I want to use cubic shipping, box in a bag. I have an item in a box that weights 10 pounds and has dimensions of 18x10x6. Is it ok/”legal” to put that boxed item into a poly mailer that is say 36 x 19 (or some dimension that will allow you to fit an 18″ long box inside a bag and fold it over to fit the overall length)? And maybe add stuffing to the sides so that it is not shaped like a box? I’m not sure what to do.

    Reply  
  26. Michelle H

    I’ve been told you can wrap your item in bubble wrap & use this method too. If that’s the case, you really don’t have length & width of an envelope. How do you note measurements?

    Reply  
    • Rockwell Sands

      Bubble wrap would be fine Michelle, you’ll just need to make sure it’s not form fit to the box! So you’ll want to give yourself plenty of extra room before cutting the bubble wrap itself. Before you put the box inside of it, try to fold it over so it looks like an envelope, and then measure the length and width before you place the box inside of it. Hope this helps!

      Reply  
  27. Lauren

    This is awesome! I was having trouble understanding the bag in a box method, and this answered all my questions! I’m excited to save even more on shipping.

    Reply  
    • Bianca

      I know people who ship box in bags and they form fit the boxes. They also buy the shipping label online through a 3rd party and not directly from USPS. Is this why they can do it and not get charged for a box?

      Reply  
      • Rockwell Sands

        Hi Bianca, this is a good question. To be honest, these shippers are doing it incorrectly, and the fact that they haven’t been charged yet is probably just luck of the draw. It doesn’t matter whether you buy the label through a third-party or from USPS directly. USPS will still charge you for a box instead of shipping a bag if they catch it…and from what I hear, USPS is really cracking down on these types of shipments lately.

        Reply  
        • Howard

          From experience, if you are shipping a box in a bag, you should always form fit the boxes. The risk of the bag becoming ripped or torn is significantly reduced. Keep in mind that your packages are tossed around on conveyor belts and by employees who hate their jobs. If its snug and tight, you won’t have any worries.

          Reply  
          • Ron

            But as I understand it, one of the requirements for ‘box in a bag’ is that the bag specifically isn’t form-fit to the box. I agree with your reasoning as to why you should keep your packaging clean and tight, but I think form-fitting the bag now makes the package ineligible for this particular rate class.

          • Rockwell Sands

            Hi Ron – you’re in fact correct about this. The “trick” here to pull this off is to protect your package contents as much as possible, all without form-fitting the bag to the box. That’s where using the right packing material comes into play!

            Simply put, if the package looks like a box, USPS is going to charge you for shipping a box.

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