Is Cubic Shipping Right for Your Business?

Under Cubic, businesses are charged based on the package’s dimensions, not weight

  • Written by Meg Thunell
  • Published on July 27, 2021
  • Time to read 9 minutes

While the technologies used to manage and ship products have changed dramatically over the last century, the business model for shipping companies looks almost the same. For decades, shipping companies have offered small businesses a single pricing formula based on weight and distance.

Think of it this way: a 40” smart TV weighs 20 pounds. So does a 20-pound dumbbell.

But the box the TV comes in is 43”x23”x5”, and the dumbbell can fit in a giant shoebox. With traditional shipping models, you’d pay the same amount to ship both a 40” smart TV and a single dumbbell to your store in Duluth even though the TV box will take up more space in the truck.

The United States Postal Service (USPS) has developed an innovative program to meet the modern needs of many small businesses by changing shipping prices for small packages.

Welcome to USPS Priority Cubic.

What is USPS Cubic mail?

Under Cubic, businesses are charged based on the package’s dimensions instead of the package’s weight. This means it costs less to ship small, heavy packages with Cubic than with traditional methods.  

And Cubic doesn’t just offer lower prices. It includes USPS priority mail delivery within 1 to 3 business days and free package tracking.

It’s a great deal if your business regularly ships things like clothing, candles, food, small home goods, books, subscription boxes, etc.


If it’s so great, why isn’t everyone using Cubic?

Cubic is a very specific program with strict rules that make it an excellent solution for some businesses but not others. 

If you want an in-depth overview of Cubic, check this out, but here are the basics:

  1. USPS Cubic mail is only available to businesses that ship at least 50,000 packages annually.
  2. Packages shipped with priority Cubic shipping have to weigh less than 20 pounds.
  3. USPS Cubic box, soft package, or priority mail poly bag dimensions must be .5 cubic feet or less with sides less than 18” (about the size of a shoebox).

What’s the Cubic formula?

USPS Cubic pricing is based solely on the size of your package. Here’s how to calculate your Cubic shipping price (sorry for the math):

1. Measure your package’s length, width, and height with each dimension rounded to the nearest quarter inch. For example, say that shoebox with your 20-pound dumbbell measures 14 x 8 x 5”

2. Multiply the dimensions (height x width x length) and then divide that number by 1728 (the number of cubic inches in one cubic foot). For your shoebox, it looks like this:

14 x 8  x 5 = 560

560/1728 = .3240

3. Round the decimal to the next tenth, meaning the .3240 of your shoebox rounds up to .4 cubic feet. (Note: you always round up, never down, with USPS Cubic).

4. Congratulations! Your package qualifies for USPS Priority Mail Cubic. 

Is Cubic right for your business?

We know that what you really want to know is, “How much will this save me?” Check out this chart:

 Zone 1–2Zone 3–4Zone 5–6Zone 7–8Zone 9
Priority Mail$23.20$29.20–$35.85$49.80–$59.75$69.35–$80.50$140.35
USPS Priority Cubic$7.32$7.32$7.32$7.32$7.32

A 20-pound Zone 1 package (something shipped 1–50 miles) costs $23.20 to ship with USPS Priority Mail, and the price increases as the distance to the destination increases.

But that same 20-pound package shipped with USPS Priority Cubic starts at only $7.32 to ship.

But here’s the deal—that $7.32 is the commercially listed starting price USPS offers.

EHub has negotiated low rates for our customers.

This means that you’ll still be saving money even after you pay for our API. But you’ll also get easy-to-print labels, order tracking history, address verification services, and insurance options.

At EHub, we know that shipping is essential, but overpaying isn’t. Drop us a line today to see how we can simplify your shipping and save you money.

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