# Volumetric weight explained

Volumetric weight is the weight a carrier assigns to a parcel based on its size: length × width × height ÷ a divisor. A 60 × 40 × 40 cm box counts as 19.2 kg at the common 5000 divisor, so if it actually weighs 8 kg you pay for 19.2 kg.

## Key takeaways

- Volumetric weight = L × W × H ÷ divisor (cm³ per kg, or in³ per lb).
- You are billed the higher of actual and volumetric weight: the chargeable weight.
- Divisors differ between carriers, services and contracts; use the one in your own agreement.
- Smaller cartons and less void fill are the fastest way to cut the bill.

## Why carriers use volumetric weight

A van, an aircraft hold or a parcel sorter fills up by space long before it reaches its weight limit when parcels are light and bulky. Volumetric weight (also called dimensional or DIM weight) lets carriers charge for the space a parcel takes. Whichever is higher, actual or volumetric weight, becomes the chargeable weight.


## How to calculate it

> **Metric:** length × width × height in cm ÷ divisor = kg   **Imperial:** length × width × height in inches ÷ divisor = lb

Measure the longest point on each side of the packed parcel and round the way your carrier specifies (many round up to the next whole centimetre or inch).


### Worked example in centimetres

| Divisor | Working | Volumetric weight |
|---|---|---|
| 5000 | 96,000 cm³ ÷ 5000 | 19.2 kg |
| 6000 | 96,000 cm³ ÷ 6000 | 16 kg |
| 4000 | 96,000 cm³ ÷ 4000 | 24 kg |



### Worked example in inches

| Divisor | Working | Volumetric weight |
|---|---|---|
| 139 | 2,304 in³ ÷ 139 | 16.6 lb |
| 166 | 2,304 in³ ÷ 166 | 13.9 lb |


[Try it with your own box](https://cartonmath.com/volumetric-weight-calculator/?unit=cm&l=60&w=40&h=40&wt=8&div=5000): The calculator shows every common divisor and the weight you are billed.


## Which divisor applies?

There is no single divisor. 5000 cm³/kg is common for international express, 6000 is the IATA ratio used by many airlines and postal services, and 4000 is used by some couriers. In the US, 139 and 166 in³/lb are common. Rates and divisors are set per carrier, per service and often per customer contract, and they change, so check your own rate card or account terms before you quote a customer.

| Divisor | Units | Where you often see it |
|---|---|---|
| 5000 | cm³/kg | Common for international express |
| 6000 | cm³/kg | Common for many postal services and airlines (IATA 1:6000) |
| 4000 | cm³/kg | Used by some express and courier services |
| 139 | in³/lb | Common US domestic and international parcel divisor |
| 166 | in³/lb | Common for some US domestic and postal services |



## How to pay less

- **Right-size the carton.** A box 5 cm smaller each way can drop a whole weight band. See [choosing carton dimensions](https://cartonmath.com/guides/export-carton-dimensions/).
- **Cut void fill.** Air pillows and loose paper add size, not protection, when the product could sit tighter.
- **Pack flat where you can.** Flat-packed or nested products give a much lower L × W × H.
- **Compare divisors when choosing a service.** The same box is 20 % lighter at 6000 than at 5000.
- **Consolidate.** Several small light parcels on one pallet may be charged differently from many separate parcels.


## Volumetric weight in air and sea freight

Air cargo works the same way, usually at 1:6000 (1 m³ counts as 166.67 kg). Sea freight does not use a divisor; LCL is charged per revenue ton, the larger of cubic metres and metric tons. See [air freight chargeable weight](https://cartonmath.com/guides/air-freight-chargeable-weight/) and [how to calculate CBM](https://cartonmath.com/guides/how-to-calculate-cbm/).

## FAQ

**What is the difference between volumetric weight and actual weight?**
Actual weight is what the parcel weighs on a scale. Volumetric weight is calculated from its size. The carrier charges the higher of the two.

**Is the divisor 5000 or 6000?**
Both are common: 5000 cm³/kg for many international express services, 6000 for many airlines and postal services. Your carrier agreement decides.

**How do I calculate volumetric weight in inches?**
Multiply length × width × height in inches and divide by the carrier's divisor, often 139 or 166, to get pounds.

**Does volumetric weight apply to sea freight?**
No. Sea LCL is charged on the larger of cubic metres and metric tons; FCL is charged per container.

Source page: https://cartonmath.com/guides/volumetric-weight-explained/
Updated: 2026-10-06
Publisher: CartonMath (https://cartonmath.com)