Dimensional Weight Calculator
Calculate a parcel's dimensional (volumetric) weight and compare it against actual weight to see which one a carrier is likely to bill.
12kg
Actual 8 kg vs. dimensional 12 kg.
| Package | Dimensional | Actual | Billable | Larger |
|---|---|---|---|---|
| #1 (×1) | 12 kg | 8 kg | 12 kg | dimensional |
DIM formula and divisor units
How this is calculated
dimWeight = length × width × height / divisor | billable = max(actual, dimensional)The divisor always carries its own unit pair — cm³/kg for metric, in³/lb for imperial. Switching unit systems switches to the matching divisor value; this tool never rescales the same number between the two.
Worked example
50 × 40 × 30 cm at a 5000 cm³/kg divisor: dimensional weight = 60,000 / 5000 = 12 kg. Against an actual weight of 8 kg, the billable weight is the larger of the two: 12 kg.
Dimension and weight rounding
Dimension rounding (if any) is applied to length, width and height before the formula runs; weight rounding is applied to the resulting dimensional weight before it's compared against actual weight. Carriers differ on whether and how they round at each step — this tool lets you choose, but defaults to no rounding.
Multiple package comparison
By default, total billable weight is the sum of each package rated independently — the standard rule unless your carrier has a documented shipment-level exception, which this tool does not model.
Carrier scope and limitations
5000 cm³/kg (139 in³/lb) is a widely used standard among several major carriers, but divisors vary by carrier, country and service level. Enter your own divisor first; treat any preset as a starting point that needs verification against your actual carrier agreement.
- Multiple packages
- Billable weight totals the sum of independently rated packages.
- Divisor units
- The divisor is unit-system specific and never silently rescaled.
Questions
Is the divisor universal across carriers?
No, but 5000 cm³/kg (equivalently 139 in³/lb) is a widely used standard among several major carriers for many service types. Divisors vary by carrier, country, service level and even shipment type (domestic vs. international, air vs. ground), so always confirm the exact divisor your carrier and service actually use before relying on this estimate for a real shipment.
Are weights rounded before or after comparison?
In this tool, any dimension rounding is applied before the dimensional-weight formula runs, and any weight rounding is applied to the resulting dimensional weight before it's compared against actual weight. Different carriers round at different points (some round each dimension up to the nearest whole unit first, others round only the final weight) — check your carrier's specific rule if precise billing matters.
Sources
- Dimensional Weight: DIM vs. Actual Weight Guide — PackCalc (reviewed 2026-09-16)