KG to CBM (Kilograms to Cubic Meters)
Convert KG to CBM using the sea-freight convention of 1,000 kg = 1 m³.
The quick answer
There is no physical conversion from kg to CBM, because kilograms measure weight and CBM measures volume. This converter uses the sea freight billing rule instead: 1,000 kg counts as 1 CBM. For real volume, divide the weight in kg by the density in kg per cubic meter.
- The range is wide — 1,000 kg of steel is about 0.13 CBM. In foam it can pass 10 CBM.
- A worked example — cargo at 250 kg per cubic meter is 4 CBM per 1,000 kg.
- Measure for true CBM — multiply length by width by height in meters. Include the pallet.
- Have the carton sizes? Measure real CBM with the CBM calculator.
1 kg = 0.001 m³
cubic meters (m³)
Based on the ocean/LCL ratio (1,000 kg = 1 m³). It is a billing convention, not your cargo's physical volume.
Quick reference
How to convert kilograms to cubic meters
To convert kilograms to cubic meters, multiply by the conversion factor:
Kilograms measure weight and cubic meters measure space, so the only true link between them is density: CBM = kg ÷ density in kg per m³. Freight gets around this with fixed billing ratios. Sea freight in a shared container (LCL) counts 1,000 kg as 1 CBM, which is the rule the converter above uses. Air cargo counts 166.67 kg as 1 CBM, and many road carriers 333 kg.
| Freight mode (ratio) | 1 CBM is billed as |
|---|---|
| Sea freight, LCL (1:1) | 1,000 kg |
| Road freight, common (1:3) | 333 kg |
| Express courier (÷5,000) | 200 kg |
| Air cargo (1:6) | 166.67 kg |
What a KG-to-CBM number is actually good for
Dividing kilograms by 1,000 doesn't tell you how big your cargo is — it tells you the volume at which ocean billing flips from weight-based to volume-based. If a supplier's packing list says 5,000 kg, the convention says "5 CBM equivalent": ship it in less than 5 CBM and you'll pay on the 5 t of weight; ship it bulkier and the volume becomes the chargeable figure.
That makes this conversion a quick sanity check on quotes. A forwarder quoting your 5,000 kg shipment as 12 revenue tons is telling you they measured 12 CBM — worth re-measuring before you pay for 7 CBM of loose packing.
Break-even density: which side of 1,000 kg/m³ is your cargo on?
Divide actual weight by actual volume to get density. Above 1,000 kg/m³, ocean LCL bills you on weight; below it, on volume. Machine parts at 850 kg packed into 0.6 m³ come out at 1,417 kg/m³ — solidly weight-rated — while furniture at 850 kg spread over 4 m³ (213 kg/m³) pays for its bulk.
For air freight the break-even sits at about 167 kg/m³, which is why almost all air cargo except metals and liquids is billed on volumetric weight. If your cargo sits near a break-even, tighter packing directly cuts the freight bill.
Frequently asked questions
How many kg are in 1 CBM?
It depends on the cargo. One cubic meter of water weighs 1,000 kg, and one of steel about 7,850 kg. For billing, sea freight counts 1 CBM as 1,000 kg, air cargo as 166.67 kg, and many road carriers as 333 kg.
Why is 1 CBM 167 kg?
Because air cargo uses a 1:6 ratio: length × width × height in centimeters, divided by 6,000. A cubic meter is 1,000,000 cm³, and 1,000,000 ÷ 6,000 = 166.67 kg. It makes light, bulky air cargo pay for the space it takes.
Is 1 cubic meter equal to 1 kg?
No. A cubic meter is a volume and a kilogram is a weight. A cubic meter of water weighs 1,000 kg; a cubic meter of foam weighs only a few kilograms. A kg-to-CBM figure is a billing rule, not physics.
How many CBM is 1,000 kg?
1 CBM by the sea-freight billing rule. The real space 1,000 kg takes can be about 0.13 m³ for steel or more than 10 m³ for foam, so measure the cargo for the true figure.
How do I work out my shipment's real CBM?
Measure each piece in meters, multiply length × width × height, and add up the pieces, pallets included. By sea you then pay on whichever is bigger: the CBM or the weight in tonnes.