USPS cubic tier calculator
Find your package's USPS cubic pricing tier.
How it works
USPS cubic pricing charges small, heavy packages by volume tier rather than weight. Each dimension is rounded down to the nearest quarter inch, the three are multiplied, and the result in cubic feet falls into a tier in steps of 0.1.
Because weight doesn't matter up to the limit, cubic pricing favors dense products in small boxes. Trimming a quarter inch off one side can drop a package into a cheaper tier. Eligibility, tiers and which services offer cubic pricing change from time to time and often depend on your shipping software or account, so confirm on usps.com.
Results are estimates based on typical industry values. Confirm final specifications with your supplier or carrier.
Frequently asked questions
How is USPS cubic tier calculated?
Round each side down to the nearest ¼ inch, multiply, divide by 1,728, then round up to the next 0.1 cubic foot.
What is the weight limit for USPS cubic?
Typically 20 lb, with a maximum of 0.5 cubic feet. Check current USPS rules for your service.
Related articles
- USPS cubic pricing explained
How USPS cubic pricing works, how tiers are calculated from rounded-down dimensions, eligibility, and which packages benefit most.
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