A Cheat Sheet on USPS Cubic Pricing

USPS Priority Mail Cubic pricing is a specialized USPS service that offers cost-effective shipping options based on package dimensions and weight. It can be one of the most cost-effective options for e-commerce businesses. But, what is it exactly, and how do you qualify for it? Check out this cheat sheet to learn more now.

What is USPS Priority Mail Cubic Pricing?

USPS Cubic pricing is a lesser-known part of USPS’s Priority Mail program that is generally only accessible by businesses that ship more than 50,000 packages a year. USPS Cubic pricing rates are determined by package size and distance traveled, with shipping distance (the zone or distance the package travels) being a key factor in calculating rates, as opposed to weight. So, for companies that ship smaller, heavier items, it can be a great option.

How Do You Qualify for USPS Priority Mail Cubic Pricing? 

As mentioned above, normally you'd have to be a large company that ships at least 50,000 packages per year, but if you use Shippo, you will not only qualify, but can save up to 89% on USPS Priority Mail Cubic pricing. That's because Shippo is able to combine all of its package volume to allow users to take advantage of significant savings without needing to meet the traditional volume of shipping required.

Are There Package Requirements?

Packages must:

• Weigh less than 20 pounds
• Measure up to 0.5 in cubic feet
• Use a box that meets the size and weight requirements for Priority Mail Cubic
• Have sides that are less than 18 inches; if a side is too close to this measurement, it might be disqualified
• Fit the quantity requirements of 50,000+ packages shipped annually, unless using Shippo

Steps to calculate your package’s cubic feet include:

• Measuring its length, width, and height
• Each dimension should be rounded down to the nearest quarter inch (these are your rounded measurements; if applicable, and already under 18 inches)
• Multiply the three rounded measurements (length, width, and height) and divide by 1,728

This is your package’s cubic foot measurement. Is it less than 0.5? If so, then it passes that particular requirement for USPS Cubic rates.

Here’s an example. Say you have a package that is 8 x 5 x 6.6 inches in size. First, you’d round down to the nearest quarter inch for any sides that are over; so it would be 8 x 5 x 6.5 inches. Then, you’d multiply those numbers, bringing it to 260. Now, divide by 1,728. The result? A cubic feet value of 0.150—which means this package qualifies. These cubic tier measurements are used to determine the appropriate pricing tier for the package.

Although these packages are often square or rectangular in shape, they don’t have to be, as long as they meet size requirements. They can, in fact, be envelopes. In that case, you’ll need to measure the item before putting it into an envelope. The longest dimension (meaning length, width, or height) can’t be more than 18 inches, with the smallest one needing to be two inches or smaller. When you add up the longest dimension and the next longest one, the sum can’t be more than 36 inches. Note: tubes or rolls will not qualify.

Measuring Packages for Cubic Pricing

Accurately measuring your packages is essential to unlock the savings offered by USPS Cubic Pricing. Whether you’re a high volume shipper or a small business looking to save money on shipping costs, following the right steps ensures your packages qualify for the most cost-effective options.

Here’s how to measure your package for USPS Cubic Pricing:

1. Measure Length, Width, and Height: Use a ruler or tape measure to determine the outside dimensions of your package in inches. Be sure to include any packaging material, as USPS bases cubic pricing on the full outside dimensions.
2. Round Down to the Nearest Quarter Inch: For each measurement—length, width, and height—round down to the nearest quarter inch. For example, if your width is 7.8 inches, use 7.75 inches for your calculation. This step is crucial for staying within the cubic tier limits and ensuring you don’t exceed the maximum allowed size.
3. Calculate Cubic Feet: Multiply the length, width, and height (all in inches) to get the total cubic inches. Then, divide that number by 1,728 to convert it to cubic feet. This cubic feet measurement determines which pricing tier your package falls into.
4. Determine the Correct Cubic Tier: USPS Cubic Pricing uses five tiers, ranging from 0.1 to 0.5 cubic feet. Compare your calculated cubic feet to the tier chart to find your package’s pricing tier. Staying within a lower tier can mean significant savings, especially for small and heavy packages.
5. Special Considerations for Soft Pack and Padded Envelopes: If you’re shipping in a soft pack or padded envelope, measure the length and width separately, then add the two measurements together. This method helps ensure you meet the minimum package requirements for these packaging types.
6. Check Minimum and Maximum Requirements: Make sure your package does not exceed 18 inches on any side and is at least 2 inches wide. Packages must also be under 0.5 cubic feet to qualify for cubic rates.
7. Use the Right Formula: Remember, the formula is: (Length x Width x Height) ÷ 1,728 = Cubic Feet. Double-check your math to avoid surprises at the post office.

By carefully measuring and calculating your package dimensions, you can determine the correct cubic tier and take advantage of discounted rates through USPS Cubic Pricing. This process helps both high volume shippers and small shippers control shipping costs, especially when sending small and heavy packages. With accurate measurements and the right packaging, you’ll be able to ship packages efficiently and maximize your savings with USPS Priority Mail Cubic rates.

USPS Cubic Rates and Savings

There are five different pricing tiers in this shipping program. To figure out your rate, pick the appropriate tier:

• 0.1: up to .10 cubic feet
• 0.2: more than .10 and up to .20 cubic feet
• 0.3: more than .20 and up to .30 cubic feet
• 0.4: more than .30 and up to .40 cubic feet
• 0.5: more than .40 and up to .50 cubic feet

Using that info, you can find your USPS Cubic rate by using these charts

Now, compare that rate to what you've been paying to find your cost savings on this package. Estimate how many packages of each pricing tier you'll likely ship during a year, and you'll have a strong sense of your potential annual savings. 

Examples of Items That Benefit from USPS Cubic Pricing

If your business, for example, provides customers with subscription boxes that contain relatively small but often heavy items, USPS Priority Mail Cubic pricing could be a great option. Or, let's say that you sell antique reference books, paperweights, hand weights for exercising, personalized stones for patios (under 20 pounds, of course), and you get the idea. Small. Heavy. Traditionally expensive to ship, but not with cubic pricing.

Benefits for Businesses of All Sizes

We see it all the time—big companies leveraging volume discounts that smaller businesses simply can't take advantage of. But with Shippo, the USPS Priority Mail Cubic pricing program levels the playing field, allowing e-commerce companies of all sizes to benefit from some of the lowest shipping rates available for packages that fit the size parameters. Plus, delivery is fast, too—generally within one to three days in the USA. 

FAQ: USPS Priority Mail Cubic Pricing

1. What is USPS Priority Mail Cubic Pricing and who is it best for?
USPS Cubic Pricing is a discounted Priority Mail service where rates are based on package size and distance, not weight. It’s ideal for shipping small, heavy items—such as subscription boxes, books, hand weights, paperweights, and similar products.

2. Do I need to ship 50,000 packages a year to qualify for Cubic pricing?
Normally yes—but not with Shippo. Shippo aggregates volume across all customers, giving any business access to USPS Cubic rates and savings up to 89%, without meeting USPS’s 50,000-package minimum.

3. What are the size requirements for Cubic packages?
To qualify, packages must:
– Weigh under 20 lbs
– Measure under 0.5 cubic feet
– Have no side longer than 18 inches
– Use packaging that fits Priority Mail Cubic rules (envelopes allowed; tubes/rolls not allowed)

Cubic feet are calculated using:
(Length × Width × Height) ÷ 1,728, rounding each dimension down to the nearest ¼ inch.

4. How do I determine which Cubic pricing tier my package falls into?
Once you calculate cubic feet, compare it to USPS’s five tiers (0.1 through 0.5 cubic feet). Your tier determines your rate—the smaller the tier, the lower the price. Businesses can estimate annual savings by mapping how many packages fall into each tier.

‍