Calculate DIM weight from package dimensions, choose imperial or metric units, and compare dimensional weight with actual scale weight.
Formula reviewed September 6, 2026 · Runs locally in your browser
Quick answer
Dimensional Weight Calculator quick answer
Formula: Dimensional weight = length × width × height ÷ DIM divisor. Billable comparison weight is the greater of dimensional and actual weight before carrier-specific rounding/rules.
Example: An 18 × 12 × 10 inch package has 2,160 cubic inches. Using a divisor of 139 gives about 15.54 lb dimensional weight, above an 8 lb actual weight.
An 18 × 12 × 10 inch package has 2,160 cubic inches. Using a divisor of 139 gives about 15.54 lb dimensional weight, above an 8 lb actual weight.
What to do with the result
Use the unit system and divisor that apply to the shipment you are modeling. The presets are convenient starting points, not carrier promises. Carrier divisors, rounding rules, oversize rules and account-specific terms vary, so verify the final billable weight before purchasing postage.
Imperial and metric formulas
For imperial inputs, DIM weight in pounds = cubic inches ÷ divisor. For metric inputs, DIM weight in kilograms = cubic centimeters ÷ divisor.