USPS Priority Mail Cubic®

Learn everything you need to know about USPS's service that could save you up to 89% off your Ecommerce shipments.

What is Cubic Pricing?

USPS Priority Mail Cubic® pricing is USPS's fastest and cheapest ways to ship Ecommerce packages, specifically those that weigh between 1 - 20 pounds. These discounts are as much as 89% off the price you pay at the post office.

Packages that qualify for USPS Priority Mail Cubic® are typically delivered anywhere in the USA between 1 - 3 days and include door-to-door tracking so that you and your customer can keep an eye on their prized goods.

Does My Package Qualify?

Packages must meet the following criteria to qualify for Priority Mail Cubic®:

  • Weighs less than 20 lbs
  • Each side is less than 18 inches in length
  • Total package is less than 0.5 cubic feet

If any single side is larger than 18 inches, your package will not qualify. Even if more that one side is close to 18 inches, it's likely too large to qualify. Tubes and rolls do not qualify.

Calculate Cubic Feet

To calculate the total cubic feet, use this formula:

(Length x Width x Height)/1,728 = Cubic Feet

Once you have your cubic feet calculated, your package will fall into one of these five tiers:

  • Tier 1: Packages up to .10 cubic feet
  • Tier 2: Packages more than .10 and up to .20 cubic feet
  • Tier 3: Packages more than .20 and up to .30 cubic feet
  • Tier 4: Packages more than .30 and up to .40 cubic feet
  • Tier 5: Packages more than .40 and up to .50 cubic feet

USPS Cubic Pricing By Zone for Packages Less than 20 Lbs

Cubic Ft
(up to not over)






Zone 1 & 2






Zone 3






Zone 4






Zone 5






Zone 6






Zone 7






Zone 8






Zone 9






Find USPS Priority Mail Cubic® Pricing by Shipping Zone

Once you have found the total cubic feet of your package, finding your price using USPS Priority Mail Cubic® is easy. Just use the following chart (or visit to find the price for the corresponding shipping zones.

Remember, even if your package fits within the cubic feet requirements, it must be less than 20 lbs.

Does My Business Qualify?

That depends on how you purchase your USPS shipping label.

USPS Priority Mail Cubic® isn't available by walking into the post office, so you will need to use a USPS technology partner like SmartShyp in order to access these discounted rates.

You can create an account and get started for free today.

Use USPS Priority Mail Cubic with SmartShyp

Create a free SmartShyp account today and speak with a one of our Shipping Consultants about saving up to 89% off your shipping rates using USPS Priority Mail Cubic® pricing. We'll help you make sure it's the best fit for your business and show you how to start saving money and time using the powerful tools inside of SmartShyp.


We get it. Sometimes seeing is believing. Fill out the form below and one of our team members will give you a personal walk-thru of SmartShyp to show you how it can help you save time and save money.

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