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DimCheck

Dimensional Weight Calculator

Enter your package dimensions and actual weight to see the dimensional (DIM) weight and billable weight every major US carrier would compute — side by side, from the same input.

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Use a custom DIM divisor only if your shipping agreement specifies one. It applies only to this calculation — official carrier rules are never changed.

Safety allowance is a planning buffer for packaging variation, not a prediction of carrier measurement error.

Monthly shipments power the Business Impact metric (excess billable weight × volume).

What this means

Carriers charge for the space a package takes, not just its weight. Dimensional weight is your package's volume converted into a weight using a divisor. Billable weight is the greater of actual weight and DIM weight — so a big, light box can bill far above its actual weight.

Relevant rules

FedEx and UPS Daily use 139 in³/lb; UPS Retail uses 166; USPS uses 139 for packages over one cubic foot; DHL Express uses 5,000 cm³/kg. Each carrier rounds dimensions and DIM weight its own way — DimCheck applies each carrier's published rule, verified against official documentation on the carrier rules page.

Worked example

A 24 × 18 × 12 in box has a volume of 5,184 in³. At FedEx's divisor of 139 that is 37.3 lb, rounded up to 38 lb DIM weight. If the box weighs 8 lb, FedEx bills 38 lb — 375% above actual weight. UPS Retail would compute 5,184 ÷ 166 = 31.2 → 32 lb for the same box.

Potential action

If DIM weight exceeds actual weight, try the box size optimizer to find smaller dimensions that bill less — or run the surcharge checker to see whether the box is near an additional-handling threshold.

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