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Save Money With USPS Priority Mail Cubic

You’re looking for an efficient and cost-effective way to send packages for your business and you’ve heard about USPS Priority Mail Cubic.

Could you save money by opting for this shipping method?

Let’s take a look…

What is USPS Priority Mail Cubic?

priority mail cubic boxes

For those who send compact yet weighty packages, USPS® Priority Mail Cubic offers an exceptional cost advantage. It uses a unique pricing structure within the Priority Mail® service, tailored for smaller parcels.

Under this pricing system, the charges are determined by the dimensions of the package rather than its weight.

Packages can weigh up to 20 pounds and should not exceed 0.5 cubic feet in size.

It’s worth noting that Priority Mail Cubic is not accessible through traditional post office counter services.

The specialized rate is exclusively available to account holders with access to USPS Commercial Pricing.

How to Use Priority Mail Cubic

priority mail cubic boxes

Using Priority Mail Cubic is relatively straightforward, but it does require adherence to specific guidelines:

Eligible Packages

Priority Mail Cubic is designed for parcels and packages with dimensions of up to 18 inches by 18 inches by 18 inches and a maximum weight of 20 pounds.

These packages should be dense and compact, allowing them to fit within a specific cubic measurement.

Cubic Tier Calculation


The pricing for Priority Mail Cubic is based on the cubic tier, determined by the package’s cubic volume in cubic inches.

The formula for calculating cubic pricing is as follows:

Step 1

Measure your package’s outer dimensions If any of the measurements exceed the nearest quarter inch, round down to the nearest quarter inch (for example, 4.6 inches turns into 4.5 inches)

Step 2

cardboard boxes
  • Multiply Length x Width x Height, and divide the result by 1728.
  • For example, to calculate the Cubic tier for a box that is 10.3″ x 9.5″ x 2″ Round down to 10.25″ x 9.5″ x 2″
  • Multiply 10.25″ x 9.5″ x 2″ = 194.75
  • Divide 194.75 / 1728 = .112

Because this package is just over 0.1 cubic feet, it is the 0.1 cubic feet pricing tier.

If it were a slightly larger box (such as 11×10.5×3) it would be in the 0.2 pricing tier instead.

Priority Mail Cubic Pricing Tiers

price and value

USPS offers several cubic pricing tiers, ranging from 0.1 to 0.5 cubic feet.

To get the best rate, packages should be efficiently packed to fit within a specific cubic tier.

USPS Priority Mail Cubic Prices By Zone (Oct 2023)

Zone 1 and 2$7.54$8.02$8.25$8.37$8.50
Zone 3$7.81$8.20$8.62$8.85$9.07
Zone 4$8.05$8.49$9.01$9.57$10.04
Zone 5$8.37$9.12$10.03$11.83$13.18
Zone 6$9.18$10.96$13.48$15.92$17.79
Zone 7$9.77$11.62$15.22$18.73$22.31
Zone 8$10.43$12.67$17.93$21.59$25.74
Zone 9$18.56$25.09$34.46$42.67$51.21

Just with other USPS services, you need to properly address and label your packages.

You can purchase Priority Mail Cubic labels from USPS or create your own labels that adhere to USPS guidelines.

Advantages of Priority Mail Cubic


1. Cost-Effective

One of the most significant advantages of Priority Mail Cubic is its cost-effectiveness for small, dense packages.

Since pricing is based on cubic volume and not weight, it can often be more economical compared to traditional Priority Mail or other shipping services for eligible packages.

2. Predictable Pricing

Priority Mail Cubic offers consistent and predictable pricing based on cubic volume tiers.

This allows businesses to calculate shipping costs more accurately and potentially save on shipping expenses.

3. Fast Delivery


Priority Mail Cubic packages are still part of the USPS Priority Mail service, which generally provides fast and reliable delivery, often within 1-3 business days.

4. Free Package Pickup

USPS offers free package pickup services for Priority Mail Cubic shipments, making it convenient for businesses and individuals who have multiple packages to send.

5. Tracking and Insurance

Priority Mail Cubic packages come with USPS Tracking and up to $50 of insurance coverage, giving you peace of mind and visibility into your shipments.

Restrictions and Considerations


While Priority Mail Cubic is an excellent choice for many shipments, there are some restrictions and considerations to keep in mind:

Package Size and Weight

Priority Mail Cubic is specifically designed for smaller, dense packages with a maximum weight of 20 pounds and dimensions not exceeding 18 inches by 18 inches by 18 inches.

Commercial Pricing Only

pricing calculator

Priority Mail Cubic is only open to shippers who have access to Commercial Pricing.

This means you have to have a commercial account with USPS with this shipping option enabled before you can use it.

That being said, there are third-party companies available that will allow you to order priority cubic services via their platforms.

Zone-Based Pricing

Like other USPS services, the cost of Priority Mail Cubic can vary depending on the destination and distance.

The cubic volume pricing tiers are consistent, but the total cost may vary based on where you are shipping your package.

Cubic Measurement Accuracy


It’s crucial to accurately measure the cubic volume of your package to determine the correct pricing tier.

Miscalculations can result in incorrect postage and delays.

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