Volumetric weight calculator for couriers, air, sea and road freight
This volumetric weight calculator (also called a dimensional weight or DIM weight calculator) works out what a carrier will bill you for. Enter the length, width and height of each box with its actual weight, pick the carrier’s divisor, and it shows the volumetric weight, the actual weight and the chargeable weight — whichever is greater — for one box or a whole list of boxes.
It works in centimetres and kilograms or inches and pounds, with the common rules built in: 5,000 cm³/kg for express couriers, 6,000 cm³/kg for IATA air cargo, 139 and 166 in³/lb for US carriers, and the 1 m³ = 1,000 kg ratio of sea freight. Online sellers, exporters and anyone sending a light but bulky parcel can see in seconds whether a smaller box would cut the bill.
How to use the Volumetric Weight Calculator
- Choose cm · kg or in · lb. Existing sizes convert when you switch.
- Pick the divisor your carrier publishes, or choose “Custom divisor” and enter its number and unit.
- Enter each box: quantity, length, width, height and the actual weight of one box. Use Add box for more sizes.
- Set the rounding your carrier uses (express services usually round up to the next 0.5 kg) and whether weights are compared per box or on the whole shipment.
- Read the chargeable weight, then download the CSV or copy the summary for your booking.
Volumetric Weight Calculator features
Many boxes at once
A list of box sizes with quantities; each row shows its own volumetric and chargeable weight, and the totals update as you type.
Carrier divisors built in
Express 5,000, IATA 6,000, US 139 and 166, sea 1:1,000 and road 1:333, plus any custom divisor in cm³/kg or in³/lb.
Per box or per shipment
Parcel carriers compare each box; air and sea cargo compare the whole consignment. Both are one switch away.
Carrier rounding rules
Round sides up to whole centimetres or inches and round the billed weight up to 0.5 or 1 kg/lb, as carriers do.
US postal 1 ft³ rule
Optionally ignore dimensional weight for boxes of 1,728 in³ or less, the threshold the US postal service applies.
CSV and summary
Download every row as a spreadsheet or copy a plain-text summary to paste into a booking or email.
The volumetric weight formula
Volumetric weight = length × width × height ÷ divisor. With centimetres the result is in kilograms; with inches it is in pounds. The chargeable weight is the greater of the actual weight and the volumetric weight, after the carrier’s rounding.
Worked example: a 60 × 40 × 40 cm carton weighing 8 kg has a volume of 96,000 cm³. At 5,000 cm³/kg its volumetric weight is 96,000 ÷ 5,000 = 19.2 kg, rounded up to 19.5 kg — more than twice the actual weight, so you pay for 19.5 kg. The same box under the IATA 6,000 rule is 16 kg.
The divisor is really a density: 5,000 cm³/kg means the carrier assumes at least 200 kg per cubic metre, 6,000 means 166.7 kg/m³, and sea freight’s 1:1,000 means one tonne per cubic metre. Anything lighter than that density is billed on space instead of mass.
Common divisors (as of 19 October 2026)
Your contract wins over any published figure: negotiated accounts often have their own divisor, and some carriers use 4,000 cm³/kg in certain markets. Enter it as a custom divisor.
| Rule | Divisor | Where it is used |
|---|---|---|
| Express courier | 5,000 cm³/kg | International express networks and many domestic couriers; one major express network publishes L × W × H ÷ 5,000 |
| Air cargo | 6,000 cm³/kg | IATA air-freight convention (1 m³ = 166.67 kg) |
| US commercial | 139 in³/lb | US parcel carriers’ daily and commercial rates; the US postal service moved to 139 on 12 July 2026 |
| US retail / legacy | 166 in³/lb | Retail counter rates; the US postal factor before 12 July 2026; ≈ 6,000 cm³/kg |
| Sea freight (LCL) | 1 m³ = 1,000 kg | Billed per revenue tonne: the greater of tonnes and cubic metres |
| Road freight | 1 m³ = 333 kg | A common ratio for groupage; hauliers vary, check the quote |
How to cut volumetric charges
- Use the smallest box that protects the item; 2 cm of extra space on every side of a 30 cm cube adds about 45% to its volume.
- Measure the longest point of each side, including bulges, and round the way your carrier does — US carriers round every side up to the next whole inch.
- Polybags and mailers for soft goods avoid dimensional weight almost entirely.
- For air cargo, consolidating many small boxes onto one pallet lets dense and light items offset each other on the shipment total.
- Then compare carriers with the shipping cost calculator, or work out storage and fulfilment fees with the fulfilment fee calculator. Converting units? Use the weight converter.
Volumetric Weight Calculator FAQ
How do I calculate volumetric weight in cm?
Multiply length × width × height in centimetres and divide by the carrier’s divisor, usually 5,000 for couriers or 6,000 for air cargo. The answer is in kilograms: 50 × 40 × 30 cm ÷ 5,000 = 12 kg.
What is the difference between volumetric weight and chargeable weight?
Volumetric weight is the weight implied by the box’s size. Chargeable weight is what you pay for: the greater of the actual and volumetric weight, rounded up by the carrier.
Which divisor should I use for air freight?
Air cargo booked through a forwarder normally uses the IATA ratio of 6,000 cm³/kg. Express couriers carrying parcels by air usually use 5,000 cm³/kg. Check the rate sheet you were given.
Is dimensional weight the same as volumetric weight?
Yes. “Dimensional weight” or “DIM weight” is the usual US term, measured in inches and pounds (divisor 139 or 166); “volumetric weight” is the common term elsewhere, in centimetres and kilograms.
How is sea freight volumetric weight calculated?
LCL sea freight is charged per revenue tonne: 1 m³ counts as 1,000 kg, and you pay on whichever is greater. A 0.5 m³ consignment weighing 300 kg is charged as 0.5 revenue tonnes (500 kg).
Does every carrier round the same way?
No. Many express services round chargeable weight up to the next 0.5 kg, US carriers round each side up to a whole inch and the weight up to a whole pound. This calculator lets you choose both roundings; your carrier’s invoice is final.