Before you buy the postage · screenshots

Billable Weight

Dimensional weight for USPS, UPS and FedEx side by side, with each carrier's own threshold rules applied rather than one formula for all three.

Screenshots, not a working copy. This product is a single self-contained HTML file, so publishing a usable one here would be handing it out for free. What you see below is the real tool running, photographed at full page height with the values shown — nothing is mocked up, redrawn or retouched.

What it looks like

A 14 x 12 x 10 box weighing 3.2 lb, zone 7.
A 14 x 12 x 10 box weighing 3.2 lb, zone 7. Under one cubic foot, so USPS bills the actual 3.2 lb (rounded to 4 lb). UPS and FedEx have no size threshold at all and bill 13 lb for the same parcel. That gap is the whole point of the tool.
12 x 12 x 13 in zone 3 — the boundary, on the other side of it.
12 x 12 x 13 in zone 3 — the boundary, on the other side of it. A 12 x 12 x 12 box is exactly one cubic foot and must not trigger USPS dimensional pricing; 12 x 12 x 13 is over it. Zone 3 is outside zones 5-9, which is a separate condition again. Both are tested.

What I ran before shipping it

  • 91 assertions across 8 box scenarios.
  • USPS moved its divisor from 166 to 139 on 12 July 2026, roughly 19% more billable weight. Anything still dividing by 166 understates the cost.
  • Each side rounds up to the next whole inch before the volume is worked out. The tests use a box where rounding sides first and rounding the volume after give different answers (5 lb vs 4 lb), so they prove which method the tool uses.

Get it

Billable Weight — $1

One HTML file. Runs entirely in your browser: no upload, no account, works offline once the page is open.

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