How to Avoid Paying Increased Dimensional Weight Shipping Rates

By Rob Zaleski
Jun 4, 2019

dimensional weight shipping rates header

The rates in this blog are the 2021 USPS shipping rates. For the current 2023 USPS rates, visit our USPS 2023 Shipping Rate Changes: Flat Rate, Priority, First Class, w/Tables blog!

The USPS dimensional weight changes that were proposed earlier this year take effect on June 23. If you’re not familiar with the changes that are coming, we’ve done a complete breakdown of the dimensional weight shipping rates changes here. In a nutshell, USPS will extend dimensional weight shipping rates across the board for Priority Mail, Priority Mail Express, and Non-lightweight Parcel Express for all packages whose volume (Lenth x Width x Height) is greater than one cubic foot. UPS and FedEx already apply dimensional weight to shipments but use a different divisor in their calculations than USPS will be using.

If you ship larger items, you may end up paying more to ship them based on their volume rather than their physical weight. This could be a problem for some retailers who are already operating on razor-thin shipping margins. In this article, we’re going to break down a couple of ways you can try to avoid paying these increased dimensional weight shipping rates by shipping smarter.

Note: As of October 19, 2022, ShippingEasy now offers the lowest USPSⓇ shipping rates in the industry, and the rates reflected in this blog are prior to this change and may not be accurate. For more information on these new rates, check out our blog!

Make Shipping Easy with a 30-day free trial !

Optimize your packing

You may have just become accustomed to grabbing whatever box size you have handy, filling it with some extra shipping materials like packing peanuts, kraft paper, or packaged air, and sending your products out the door. Now, if that box measures more than one cubic foot, you could pay more than you bargained for to send that package.

So what options do you have? One option is to start using boxes that more closely match the size of your products. This might mean stocking up on some boxes of varying sizes to accommodate orders of different product combinations. You can order boxes of various sizes through sites like Brandable Box (one of our recommended partners) or ULINE. Though there’s an upfront cost associated with it, you could save in postage later by not having to pay for unused space in a box.

You may even consider splitting some orders. This is an easy process to do in a shipping platform like ShippingEasy.

So, let’s say you sell custom lamps. They don’t weigh much, probably just under 4 lbs, but they are bulky to ship. You use a 20 x 14 x 8 box to ship two lamps in; from Houston to Miami, which is Zone 5. Now, let’s do some math.

(The rates calculated will be USPS Commercial Rates like you’d get through ShippingEasy.)

Original shipping cost for 8 lb Priority Mail package: $18.04
BUT, 20x14x8 = 2,240
Divide that by 1,728 (1 cubic foot) = 1.23 (greater than 1 means it qualifies for dimensional weight)
Divide the volume of the package (LxWxH) by the USPS divisor of 166 = 13.49 (round to 14 lbs, which is your new “weight”)
New Dimensional Weight cost: $28.98

Now, if you split those two lamps into separate packages weighing about 4 lbs in boxes that don’t qualify as dimensional weight (i.e. under one cubic foot), the shipping cost for each is $10.43. That means splitting them costs you $20.86 to ship, rather than the dimensional weight cost of $28.98. You just saved over eight dollars on that shipment by shipping smarter.

Skip the math! Use our dimensional weight calculator to calculate dimensional weight for USPS, FedEx, and UPS in a snap.

Look into Flat Rate options

Priority Mail Flat Rate and Regional Rate are two options that are often overlooked by online sellers, yet offer many benefits and help smart shippers save. If you’re not familiar with these two, we’ll break them down a bit.

Priority Mail Flat Rate

Using USPS-branded envelopes and boxes (which you can get delivered to your door from USPS, absolutely free) let you pay a single flat rate for a package up to 70 lbs regardless of how far it travels domestically or to APO/FPO/DPOs. The box that may apply in the case of dimensional weight is the Priority Mail Large USPS Flat Rate boxes. They measure 12” x 12” x 5.5” and you pay $19.30 regardless of the weight or distance the package is going.

It’s worth having some of these boxes on hand to see if your larger items or multiple items can fit in them, helping you avoid paying dimensional weight shipping rates on those orders.

Comparison: Regional vs. Flat Rate (For packages up to 15 lbs.)
	Regional Rate Box A 10" x 7" x 4 3/4"	Flat Rate Medium 11" x 8 1/2" x 5 1/2"
Houston to Miami	$9.55	$14.25
New York to Los Angeles	$13.54	$14.25
Dallas to San Antonio	$8.58	$14.25

Priority Mail Regional Rate

Regional Rate boxes come in two categories: Box A and Box B, each with a top-loading version and a more narrow side-loading version. Box A can contain products up to 15 lbs, and Box B up to 20 lbs. The difference between Flat Rate and Regional Rate is that distance matters. If you predominantly ship products within Zones 1-4, you may see significant savings using Regional Rate. Box B would be the more relevant one to look at when considering dimensional weight, as it measures 12″ x 10-1/4″ x 5″ for the top-loading box, and 15-7/8″ x 14-3/8″ x 2-7/8″ for the side-loading box.

2021 USPS Regional Rate	Zones 1 & 2	Zone 3	Zone 4	Zone 5	Zone 6	Zone 7	Zone 8	Zone 9
Box A	$7.83	$8.04	$8.34	$9.01	$10.89	$11.63	$12.64	$23.37
Box B	$8.23	$8.64	$9.56	$12.36	$17.50	$20.10	$22.90	$42.98

All that being said, there may be some times when it’s just not possible to use different packaging. Some items are just too large and can’t be folded/squished/tucked into a smaller box. In these events, you’ll need to be aware that the cost to ship that package will be higher, possibly significantly so. That means you’ll need to be optimizing and saving in other areas to compensate.

This is where ShippingEasy can help. We cut time from your processes, save on shipping everywhere possible, and provide you the tools to gain repeat business through email marketing. All this in a single platform. Try it free for 30 days by clicking below.