Dimensional Weight Calculator

Find a package's dimensional (volumetric) weight from its length, width, and height, then compare it with the actual scale weight to see which one a carrier will bill you for.

Quick Facts

Formula
Dimensional weight = (L × W × H) / divisor
Length, width, and height in centimeters with a divisor in cm³/kg gives the result directly in kilograms.
Billable weight
The greater of actual weight and dimensional weight
A large, lightweight box can cost more to ship than its scale weight suggests.

Your Results

Calculated
Dimensional weight
-
Per package: L × W × H ÷ divisor
Actual weight
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Per package, as entered
Billable weight
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Per package: the greater of the two
Total billable weight
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Billable weight × number of packages

Ready

Enter package dimensions, actual weight, and package count, then press Calculate.

Understanding Dimensional Weight

Dimensional weight (also called volumetric weight or DIM weight) is how shipping carriers charge for the space a package occupies, not just what it weighs on a scale. A box full of pillows or packing peanuts can be light on a scale but bulky in a truck or cargo hold, so carriers calculate a "weight" from its size and bill whichever number — actual or dimensional — is higher.

The formula

The standard formula, used across air freight and parcel carriers worldwide, is:

  • Dimensional weight = (Length × Width × Height) / Divisor

With length, width, and height measured in centimeters and a metric divisor (also called a DIM factor or volumetric factor), the result comes out directly in kilograms. The divisor represents how much volume "equals" one unit of weight under a carrier's pricing model — a smaller divisor produces a heavier (more expensive) dimensional weight for the same box size.

Common divisors

  • 5000 cm³/kg — the most widely used figure for international air freight and courier shipping (DHL, FedEx, and UPS international services all default to this).
  • 6000 cm³/kg — used by some postal services and economy/deferred shipping products, which produces a lower dimensional weight than 5000 for the same box.
  • 4000 cm³/kg — used on some volumetric-heavy tariffs (e.g. certain express or domestic services), producing a higher dimensional weight than 5000.

Carriers publish their exact divisor in their rate documentation, and it can change by service level, so always confirm the number before relying on an estimate for a real shipment. (US domestic carriers that quote in inches and pounds commonly use an equivalent formula of Length × Width × Height in inches, divided by 139 or 166 — the underlying idea is identical, only the units and divisor change.)

How billable weight is determined

Once the dimensional weight is calculated, the carrier compares it with the actual (scale) weight and bills the greater of the two — this is the "billable weight." Most carriers then round the billable weight up to the nearest 0.5 kg or whole kg (or nearest pound for imperial services), so real invoices may be a fraction higher than the raw calculation.

Why it matters

Understanding dimensional weight helps you choose packaging that minimizes wasted volume, compare quotes across carriers that use different divisors, and avoid surprise charges when shipping large-but-light items like electronics packaging, apparel, or foam-filled boxes.

Frequently Asked Questions

What is dimensional weight?
Dimensional weight (or volumetric weight) is a shipping charge based on how much space a package takes up rather than how heavy it is. Carriers calculate it as length × width × height divided by a dim factor (divisor), so a large, light box can cost as much to ship as a smaller, heavy one.
How is dimensional weight calculated?
The standard formula is Dimensional weight = (Length × Width × Height) / Divisor, with dimensions in centimeters and the result in kilograms when using a metric divisor such as 5000. Most carriers then round the result up to the nearest 0.5 kg or whole kg.
What divisor should I use?
5000 cm³/kg is the most common international air freight divisor used by DHL, FedEx, and UPS. Some postal and economy services use 6000, which produces a lower dimensional weight, while a few volumetric-heavy tariffs use 4000. Always confirm the exact figure on your carrier's published rate rules before shipping.
How do carriers decide the billable weight?
Carriers bill whichever is greater: the actual scale weight or the calculated dimensional weight. If a package is bulky but light, the dimensional weight sets the price; if it is small and dense, the actual weight sets the price.

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