Volumetric Weight Calculator
Find the volumetric weight of your parcel, the weight you’ll actually be charged for, and what it costs to ship.
Check your carrier’s current divisor; it varies by carrier, service and contract.
Carriers often round up to the next 0.5 kg or 1 lb. Simple mode uses 0.5 kg or 1 lb.
Compare actual and volumetric weightAir cargo usually compares the whole shipment; many parcel services check each box on its own.
Round each side up to a whole cm firstCharged per revenue tonne (W/M): the bigger of cubic metres and tonnes. Common rule: 1 m³ = 1,000 kg.
How your chargeable weight is worked out
Volumetric weight = length × width × height ÷ divisor. You pay for whichever is bigger: that or the actual weight.
- 1
Box volume
45 × 35 × 30 cm= 47,250 cm³
- 2
Divide by the divisor
47,250 ÷ 5,000= 9.45 kg
- 3
Bigger one wins
actual 6.2 kgsize 9.45 kg→ 9.45 kg
- 4
Round up
next 0.5 kg= 9.5 kg
Read more: the formula, a worked example, divisors, rounding and sea freight
Carriers charge for the space a parcel takes up as well as its weight. A big, light box (a lampshade, a pillow) fills a plane or van just as much as a heavy one, so they turn its size into a volumetric weight and bill you for whichever is bigger: that or the actual weight. The bigger one is your chargeable weight.
The formula
volume = length × width × height
volumetric weight = volume ÷ divisor
(divisor in cm³ per kg with cm, or in³ per lb with inches)
chargeable weight = the bigger of actual weight and volumetric weight
billed weight = chargeable weight rounded up to the carrier’s step
cost = billed weight × price per kg (or lb), at least the minimum charge, plus fuel surcharge %
sea freight W/M = the bigger of cubic metres and tonnes (1 m³ = 1,000 kg)
Worked example
A box measures 45 × 35 × 30 cm and weighs 6.2 kg. With a divisor of 5,000:
- Volume = 45 × 35 × 30 = 47,250 cm³ (0.04725 m³).
- Volumetric weight = 47,250 ÷ 5,000 = 9.45 kg.
- 9.45 kg is more than the 6.2 kg on the scale, so the chargeable weight is 9.45 kg, which rounds up to the next 0.5 kg as 9.5 kg.
- At $4.50 per kg that costs 9.5 × $4.50 = $42.75. Charged on weight alone (6.2 kg, rounded up to 6.5 kg) it would be $29.25, so the box’s size adds $13.50.
With a divisor of 6,000 the same box is 47,250 ÷ 6,000 = 7.875 kg, rounded up to 8 kg. At 6.2 kg the box could be up to 6.2 × 5,000 = 31,000 cm³ (say 35 × 30 × 29.5 cm) before its size counts.
Common divisors
| Divisor | Same as | kg per m³ | Where it’s commonly used |
|---|---|---|---|
| 5,000 cm³/kg | 138.4 in³/lb | 200 | Common for express couriers |
| 6,000 cm³/kg | 166.1 in³/lb | 166.7 | Common for air cargo and economy services |
| 4,000 cm³/kg | 110.7 in³/lb | 250 | Used by some couriers and road services |
| 139 in³/lb | 5,022 cm³/kg | 199.1 | Common for US domestic couriers |
| 166 in³/lb | 5,997 cm³/kg | 166.7 | Used for some US domestic services |
These are common values, not any one carrier’s rule. The IATA air cargo standard is commonly cited as 6,000 cm³ per kg (about 166.7 kg per m³). Divisors vary by carrier, service, route and contract, and they change: check your carrier’s current divisor. Written 13 October 2026; not checked against IATA or any carrier’s published rules.
Several boxes
Say you send two boxes of 60 × 40 × 40 cm at 10 kg each and one 30 cm cube at 30 kg, with a divisor of 5,000. Each big box is 96,000 ÷ 5,000 = 19.2 kg volumetric; the cube is 27,000 ÷ 5,000 = 5.4 kg.
- Whole shipment (usual for air cargo): volumetric 2 × 19.2 + 5.4 = 43.8 kg against 50 kg actual, so you pay for 50 kg. The heavy cube makes up for the light boxes.
- Box by box (many parcel services): 19.2 + 19.2 + 30 = 68.4 kg, or 69 kg when each box is rounded up to the next 0.5 kg.
Sea freight: CBM and revenue tonnes
Shared container (LCL) freight is usually priced per revenue tonne, or W/M (weight or measure): the bigger of the cubic metres (CBM) and the weight in tonnes, with the common rule that 1 m³ counts as 1,000 kg. A pallet of 1.2 × 1.0 × 1.5 m is 1.8 m³; if it weighs 2,400 kg that is 2.4 tonnes, so it is charged as 2.4 W/M. At $50 per W/M that is $120. Many quotes have a minimum of 1 W/M, so the 45 × 35 × 30 cm box (0.047 m³) would still pay for 1.
Tips to pay less
- Use the smallest box that protects the item. Taking 5 cm off each side of the example box (40 × 30 × 25 cm) drops it to 6 kg volumetric, so you’d pay on the 6.2 kg weight instead.
- Measure at the widest points, including bulges and handles; carriers re-measure and charge the difference.
- Ask your carrier about the divisor in your contract: going from 5,000 to 6,000 cuts volumetric weight by a sixth.
A guide for planning. Carriers can add surcharges for oversize or overweight pieces, remote areas and peak seasons that this calculator doesn’t include.
Common questions
How do you calculate volumetric weight?
Multiply the length, width and height of the box, then divide by the divisor your carrier uses. In centimetres and kilograms a common divisor is 5,000: a 45 × 35 × 30 cm box is 47,250 cm³, and 47,250 ÷ 5,000 = 9.45 kg.
What is chargeable weight?
It is the weight you are billed for: the bigger of the actual weight on the scale and the volumetric weight. A 6.2 kg parcel with a volumetric weight of 9.45 kg is charged as 9.45 kg, often rounded up to 9.5 kg.
Should I use 5000 or 6000?
It depends on the carrier, the service and your contract. 5,000 cm³ per kg is common for express couriers and 6,000 is commonly cited for air cargo (the IATA standard is usually given as 6,000 cm³ per kg). Check your carrier’s current divisor, because it varies and changes.
What are 139 and 166 in dimensional weight?
They are divisors for inches and pounds: dimensional weight in lb = length × width × height in inches ÷ 139 (or 166). 139 in³ per lb is about the same as 5,022 cm³ per kg, and 166 is about 5,997 cm³ per kg.
How is sea freight (LCL) charged?
Usually per revenue tonne, also called W/M (weight or measure): the bigger of the cubic metres and the weight in tonnes, using the common rule 1 m³ = 1,000 kg. Many quotes charge a minimum of 1 W/M.
How can I lower my volumetric weight?
Use the smallest box that protects the item, cut down tall boxes, avoid lots of void fill, and ship flat-packed where you can. Every centimetre counts because all three sides are multiplied together.
Related calculators
Made by Zulu Calculator, part of AlphaZulu LLC. Formulas are shown in full and rule figures are checked against official sources; see how we build calculators.