CBM Calculator
Work out the total cubic meters (CBM) of a shipment. Add each carton size, in cm, inches, meters or feet. Add weights too, and you will see what you are billed on: sea freight by W/M, air freight by chargeable weight. It also shows how full a 20ft, 40ft or 40ft High Cube container would be.
Total volume
Cubic feet
169.5
ft³
Sea vol. wt
4,800
kg (1 m³ = 1,000)
Air vol. wt
800
kg (÷ 6,000)
Gross weight 1,000 kg
Sea (LCL) billed on 4.8 W/M · volume governs
Air chargeable 1,000 kg · actual weight governs
Container fit · ~80% usable
Free PDF includes a watermark. Pro removes it & adds your brand.
Estimates only — container fit assumes ~80% usable volume (real packing varies with stacking and box shape). Confirm with your carrier.
How to calculate CBM
Your cartons are rarely measured in meters. Multiply the three sizes in the unit you have, then divide by the matching number:
| Sizes in | CBM = |
|---|---|
| centimeters | L × W × H ÷ 1,000,000 |
| inches | L × W × H ÷ 61,024 |
| feet | L × W × H ÷ 35.315 |
| meters | L × W × H |
In centimeters: a carton of 120 × 100 × 100 cm is 1,200,000 ÷ 1,000,000 = 1.2 CBM. Four of them are 4.8 CBM. That is the example loaded above.
In inches: a 24 × 18 × 12 in carton is 5,184 cubic inches. Fifty cartons are 259,200 cubic inches. Divide by 61,024 and you get 4.25 CBM. Many US suppliers list carton sizes in inches, so switch the calculator to “in” and type them as they are.
Measure the outside of each carton, and round up rather than down. A shipment is billed on the space it takes, so a small under-measure on every carton adds up.
CBM and what you pay for
CBM alone does not set the price. Carriers compare volume with weight and charge on whichever is larger. The calculator does this for you once you add weights.
Sea freight (LCL): W/M
LCL rates are quoted per W/M, short for “weight or measure.” Each unit is 1 CBM or 1,000 kg, whichever gives the bigger number. The example above is 4.8 CBM and 1,000 kg, so it is billed as 4.8 W/M, and volume decides. Ten 80 × 60 × 50 cm crates at 320 kg each are only 2.4 CBM, but they weigh 3,200 kg, so they are billed as 3.2 W/M, and weight decides.
Air freight: chargeable weight
Air freight converts volume to weight at 6,000 cm³ per kg, so each CBM counts as about 167 kg. You pay on the larger of that volumetric weight and the real weight. The 4.8 CBM example counts as 800 kg by volume but weighs 1,000 kg, so you pay on 1,000 kg. Some couriers use 5,000 instead of 6,000, which makes volume count for more. Check the number in your quote, or use the chargeable weight calculator to try both.
How many CBM fit in a container?
A container's CBM is its inside length × width × height. These are typical inside sizes; outside sizes are on the shipping container dimensions page. Each line or build can differ slightly:
| Container | Inside L × W × H | CBM |
|---|---|---|
| 20ft Standard | 5.9 × 2.35 × 2.39 m | 33.1 |
| 40ft Standard | 12.03 × 2.35 × 2.39 m | 67.6 |
| 40ft High Cube | 12.03 × 2.35 × 2.7 m | 76 |
You will not fill every cubic meter. Cartons leave gaps, pallets take space, and some goods cannot be stacked to the roof. The calculator plans on about 80% of the inside volume. That is our rule of thumb, not a carrier rule. For a box-by-box plan, use the container loading calculator.
Converting CBM
- • 1 CBM = 35.315 cubic feet = 1,000 liters = 61,024 cubic inches.
- • CBM to cubic feet and back: CBM to CFT · CFT to CBM
- • CBM and kilograms for sea and air: CBM to kg · kg to CBM
- • Not shipping, or measuring a tank, pipe or area? Cubic meter calculator for boxes, cylinders and area × depth.
Frequently asked questions
How do you calculate CBM?
Multiply length × width × height in meters, then multiply by the number of cartons. If you measured in centimeters, multiply the three sizes and divide by 1,000,000. Four cartons of 120 × 100 × 100 cm are 1.2 CBM each, so 4.8 CBM in total.
What is the CBM formula in inches?
Multiply length × width × height in inches and divide by 61,024, the number of cubic inches in one cubic meter. A 24 × 18 × 12 in carton is 5,184 cubic inches, or 0.085 CBM. Fifty of them come to 4.25 CBM.
What size is 1 CBM?
One CBM is a cube 1 meter long, 1 meter wide and 1 meter high, about 39.4 inches on each side. It holds 1,000 liters, which is about 35.3 cubic feet.
How do you convert CBM to cubic feet?
Multiply by 35.315. For example, 4.8 CBM is about 169.5 cubic feet. To go from cubic feet to CBM, divide by 35.315.
How many CBM fit in a 40ft container?
A standard 40ft container is about 12.03 × 2.35 × 2.39 m inside, which is about 67.6 CBM. A 40ft High Cube is about 76 CBM and a 20ft about 33.1 CBM. Boxes rarely fill every gap, so plan on loading less than the full figure.
How do you convert CBM to kg?
There is no single answer, because CBM is space and kg is weight. For billing, sea freight treats 1 CBM like 1,000 kg, and air freight treats 1 CBM like about 167 kg (the 6,000 cm³ per kg rule). Enter your real weights above to see which one you will pay on.