USPS DIM Weight Changes Go Into Effect

It’s official, folks. Starting today (June 23rd, 2019), the USPS DIM weight changes have officially gone into effect! Here’s everything you need to know about USPS’ new policy on the dimensional weight of packages.

What are the USPS DIM Weight Changes?

There are two major changes that USPS instituted when it comes to dimensional weight. First off, USPS lowered their volumetric divisor from 194 to 166. In addition, dimensional weight charges now apply to every single USPS zone, whereas it only applied to Zones 5-9 in the past. Let’s talk a little bit about both changes.

The New Volumetric Divisor

To determine the dimensional weight of a package, USPS multiplies the package’s Height x Width x Length. Then, they take that number and divide it by 166 to calculate the dimensional weight. The equation looks something like this:

DIM = (HxWxL)/166

USPS always used 194 as their volumetric divisor prior to today, which resulted in a lower dimensional weight for packages. Now, however, a lower divisor of 166 means higher dimensional weights.

DIM Weight Now Applies to All USPS Zones

Up until now, the Postal Service only applied dimensional weight charges to Priority Mail packages traveling to USPS Zones 5-9. However, DIM weight charges now apply to all the USPS Zones for packages in the following mail classes:

• Priority Mail
• Priority Mail Express
• Retail Ground/Parcel Select Ground

A Quick Example of How DIM Weight Works

When determining the price of a package, USPS (and all the other shipping carriers) will charge for postage based on whichever weight is greater: the dimensional weight or the actual weight.

If your box is 13x13x13″ then 13 x 13 x 13 = 2197 / 166 = 13.23 lbs. That means if your package’s actual weight is less than 13.23 pounds, you’re going to be charged the 13.23 pound rate instead.

How to Hedge Against the USPS DIM Weight Changes

The best way to protect yourself against the new DIM weight changes is to make sure your package dimensions are as optimized as possible. Simply put, smaller packages are less likely to be hit with dimensional weight charges. In fact, if the total volume of your package is less than 0.5 cubic feet, you won’t get hit with the DIM weight charges at all! You’ll also qualify for a special discounted mail class called USPS Priority Mail Cubic, that you can only access when you use online shipping software to buy postage.