Shipping With USPS: A Beginner’s Guide to Sending Packages with the US Postal Service

Everything you need to know to get started shipping with USPS
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If you’re running your own eCommerce business, shipping is a huge part of your everyday operation. Your packages have to reach your customers somehow, right? That’s why it’s SO important to have a strong handle on shipping with USPS. We’ll level with you: most small businesses aren’t shipping with USPS correctly! We want to make sure you know what you’re doing, so we created this guide to help you out. We covered as many basics on shipping with USPS as we could think of, so you can refer back to this guide whenever you need to! Let’s dive right in, shall we?

Table of Contents

Why Should I Ship with USPS?

Choosing the right shipping carrier can be a pickle. However, if you’re running an eCommerce business, the choice is pretty obvious. USPS is the best carrier for E-commerce businesses due to their competitive prices on shipping small, heavy parcels like subscription boxes. Also, you can easily access USPS discounts with shipping software. There’s a lot to know when it comes to all the different USPS mail classes and postage pricing tiers, but don’t fret. We’ve got you covered.

How to Purchase Postage

As anyone who’s ever mailed a letter or shipped a package knows, you need to purchase postage in order to send anything. When most people think of buying postage, they think of walking their package into the Post Office, waiting in line, and purchasing stamps at the counter. However, there are a number of ways you can buy postage in today’s day and age—and you can get hooked up with some pretty serious discounts if you’re willing to turn some stones over.

Buying at the Post Office

Like we mentioned above, nothing’s stopping you from visiting your local Post Office and buying postage. We won’t lie—sometimes it’s nice to stroll down the street on a breezy Saturday morning and drop off that care package for grandma at the Post Office. However, if you’re an E-commerce business owner shipping out a ton of parcels, you can see why this method of buying postage doesn’t make the most sense. You’ll need a quick and easy way to buy postage in bulk, and the Post Office isn’t the best destination for that.

Buying at

If you’re in the middle of Netflix binging and don’t want to leave your house, don’t worry—we won’t judge you. On a serious note: buying postage on is a convenient and relatively easy process. In fact, it can be done anywhere you have a computer, internet access, a way to measure and weigh your package*, and a printer (we recommend that you use a direct thermal label printer to print shipping labels)! You don’t even have to put on pants…but you didn’t hear that from us.

*When it comes to measuring the dimensions of your package, a ruler should do just fine. However, weighing packages accurately can get a little bit tricky. Check out some of these recommendations for postage scales.

Buying Postage via a Third-Party Postage Provider

Like we touched on in our guides Basics of Shipping for Small Businesses, a third-party postage provider is a company that provides USPS postage at discounted rates. Most of these companies hook you up with Commercial Pricing rates (but watch out for markups!). If you’re running an eCommerce business, taking advantage of those discounts can make all the difference in the world. Quite frankly, whether an eCommerce business can compete with bigger companies often comes down to buying discounted postage. Therefore, we at Shipping School ALWAYS recommend that you buy postage online through shipping software solutions.

The Two USPS Postage Pricing Tiers

There are two different USPS postage pricing tiers, which we’ve listed for you below.

The USPS Retail Rate

The USPS Retail Rate is what you’ll pay if you buy postage at the Post Office or at Needless to say, buying postage at the retail rate isn’t the best deal you can get. If you’re shipping with USPS, paying for postage at the retail rate can put a serious dent in your wallet! It’s actually not uncommon for postage to be an E-commerce business’ biggest expense outside of cost of goods sold. Therefore, it’s crucial for you to take advantage of postage discounts whenever you can.

Commercial Pricing

Formerly called “Commercial Plus Pricing,” Commercial Pricing describes the deepest level of USPS discounts available. It helps to think of Commercial rates kind of like “wholesale” USPS prices. We’ll lay it out for you simply: if you’re running an eCommerce business, you ALWAYS want to buy postage at the Commercial rate. To speak frankly, it’s the only way your small business has a shot at keeping up with the big guys. As the famed music producer and social-media personality DJ Khaled would say: “Don’t play yourself!”

Choosing the Right USPS Mail Class

When you’re shipping with USPS, you’ll need to choose which mail class to ship it in. Mail classes are simply the different mailing and shipping services USPS offers to customers. Each mail class varies based on cost, delivery timeframes, items allowed in the package, and the maximum weight. We’ve laid out a few of the most common domestic USPS mail classes below.

Priority Mail

The cheapest way to ship small packages, Priority Mail is arguably the most common USPS shipping service. Priority Mail has three defining characteristics: free package tracking, delivery between 1-3 business days, and $100 of insurance included. There are four sub-services within Priority Mail: size-based Priority Mail Cubic, weight-based Priority Mail, Priority Mail Flat Rate, and Priority Mail Regional Rate.

Priority Mail Express

This is the fastest delivery service that USPS offers. In most cases, Priority Mail Express items are delivered overnight. However, Priority Mail Express is only overnight to and from urban areas. Rural areas typically take 2 days. Priority Mail Express is guaranteed to be delivered on time; otherwise, you’ll receive a full refund. While more expensive than the other mail classes, Priority Mail Express includes free package tracking and $100 of insurance.

First-Class Mail

First-Class Mail is designated for sending flat items that weigh less than 3.5 ounces. Think items like postcards and those love letters you never sent out back in high school. This mail class is typically used for personal correspondence, business correspondence, and bills…so if you’re shipping actual products, this is something you likely won’t be worried about.

First-Class Package

First-Class Package is the cheapest way to send small packages weighing less than 16 ounces. Similar to Priority Mail, First-Class Package boasts delivery timeframes within 1-3 business days to anywhere in the United States. First-Class Package pricing is based on package weight, as well as which USPS zone it is being shipped to.

Pro Tip: The mail classes we went over here are just the tip of the iceberg! Don’t forget that there are international USPS mail classes, too.

Priority Mail Cubic: The Best Perk of Shipping with USPS

This is the part of the article where we reveal all of the secrets of the universe! Okay, maybe not, but we are about to let you in on some life-changing stuff. eCommerce business owners, TAKE HEED…because this is for you! Let’s talk about one of the four sub-services of Priority Mail: Priority Mail Cubic.

Priority Mail Cubic (or “Cubic,” for short) is a “secret” USPS mail class perfect for shipping small, heavy parcels like a subscription box. Like all Priority Mail services (and sub-services), Cubic delivery occurs between 1-3 business days, it includes package tracking and comes with $100 of insurance. However, Cubic has some restrictions that your package has to meet. We’ve outlined those below:

  • The dimensions of your package can’t be more than 18 inches each
  • Total weight of your package can’t be more than 20 pounds
  • Total volume of your package can’t be more than 0.5 cubic feet

Simply put, shipping Cubic is the cheapest AND fastest way to ship small parcels between 1 and 20 pounds. Unlike other USPS mail classes, Cubic’s pricing is determined by your package dimensions and not its weight. That means you can load your packages up with as many items as possible, and you won’t get charged based on weight! Just make sure the total weight doesn’t exceed 20 pounds.

On top of allowing you to send heavier items without affecting your shipping costs, Priority Mail Cubic offers some serious discounts on postage, since USPS only offers it at Commercial Pricing rates. In fact, there are some cases when shipping a package with Priority Mail Cubic can save you up to 87% off of what you’d pay to ship the exact same package at the Post Office!

How Can I Ship Priority Mail Cubic?

Here’s the kicker: Cubic isn’t actually something the USPS offers at their locations. It’s a bit of a “secret” item on the menu—kind of like “Animal style” at In-N-Out Burger. Typically, the only way to ship Priority Mail Cubic is to enter into a direct contract with USPS. Those contracts have strict requirements, like shipping over 50,000 parcels per year. To speak frankly, that’s an unrealistic goal for a lot of small businesses to hit.

If you’re feeling the Cubic FOMO right about now, cheer up! We’ve got some good news. There are actually several different shipping software options out there that let you access this special service. There are a ton of different options, though, and when it comes to figuring out which shipping software is the best choice for your business, well…that’s up to you to determine.

Looking for the right shipping software for you?

To get the deepest discounts on all USPS shipping services, check out our guide:

Choose the Best Shipping Software

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Post a Comment
  1. Larita Mitchell

    I feel when you deliver a package you suppose to knock on the door, not leave it in the lobby and this is constantly people getting new packages stolen because the mailman the delivery guy doesn’t knock on People door

    • LaRita Mitchell's Friend

      i often go to walmart to complain about McDonalds.


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