Dimensional weight calculator

Volumetric weight for air, express and LTL, with the divisor set to whichever convention your carrier actually uses. Enter an actual weight and it tells you which one you will be billed on.

Package

Units

Carrier convention

Pieces

Length inches

Width

Height

Actual weight (lb) optional

The divisors, and when each applies

Mode	Imperial	Metric
Air freight, IATA standard	166 in³ / lb	6,000 cm³ / kg
Express courier	139 in³ / lb	5,000 cm³ / kg
Aggressive express contracts	—	4,000 cm³ / kg
LTL dimensional rules	194 or 250 in³ / lb	—

A smaller divisor produces a larger dimensional weight, which is why express carriers use 139 where air freight uses 166. Contract rates frequently specify a divisor that differs from the published one — if your agreement names a number, use the custom field.

Why carriers charge for volume

An aircraft or a van fills up by space long before it fills up by weight for most cargo. Charging purely by weight would let a shipper fill a container with pillows for almost nothing. Dimensional weight sets a floor: you pay for the space you occupy or the weight you actually have, whichever is greater.

The practical consequence for anyone packing goods: an inch matters. A carton at 18×14×12 dims to 18.2 pounds at 166; the same goods repacked to 16×14×12 dim to 16.2. On a hundred cartons that is a real number.

Rounding

Most carriers round the chargeable figure up to the next whole pound or kilogram, and air freight commonly rounds to the next half kilogram. The calculator shows the unrounded dimensional weight and a billable figure rounded up to the next whole unit; check your tariff for the exact rounding rule before you build it into a quote.

Questions people actually ask

What is the difference between dimensional weight and chargeable weight?

Dimensional weight is the volume-derived figure — volume divided by a divisor. Chargeable weight is the one you actually pay on, which is the greater of dimensional weight and actual gross weight. Every shipment has both; only one of them ends up on the invoice.

Which divisor should I use, 139 or 166?

Use 166 in³/lb for IATA air freight and 139 in³/lb for express couriers and US domestic parcel. If you have a negotiated contract, the divisor in that contract overrides both — carriers routinely trade a better rate for a smaller divisor, which quietly raises the dimensional weight on every bulky shipment.

Does dimensional weight apply to LTL freight?

Increasingly, yes. LTL has historically rated on class and weight, but many carriers now have dimensional rules that engage on light, bulky freight, commonly at 194 or 250 cubic inches per pound. Those sit alongside linear-foot and capacity-load rules rather than replacing them.