CBM Calculator
Cubic meters, LCL revenue tons (W/M) and container fit — as you type, no sign-up.
Sea freight is sold by space. CBM (cubic meter) is the unit: L × W × H in meters, multiplied by carton count. LCL (less than container load) rates are quoted per revenue ton — the greater of total CBM and total weight in tonnes, known as the W/M rule.
Once your volume approaches ~15 CBM, ask your forwarder to quote a full 20’ container (FCL) — it is often cheaper than LCL at that size and your goods travel sealed. For air shipments, use the air freight chargeable weight calculator (÷6000) or the express calculator (÷5000) instead.
How do I calculate CBM?+
CBM (cubic meter) = length × width × height in meters. For a carton measured in cm: L × W × H ÷ 1,000,000. Multiply by carton quantity and sum across sizes — this calculator does it as you type.
What is a revenue ton (W/M)?+
LCL sea freight charges per revenue ton: the greater of the shipment’s volume in CBM and its weight in metric tonnes (1 CBM = 1,000 kg equivalence). A 2.5 CBM / 800 kg shipment pays for 2.5 revenue tons.
How many CBM fit in a 20ft / 40ft container?+
Nominal capacities are about 33 m³ (20GP), 67 m³ (40GP) and 76 m³ (40HQ), but real-world usable capacity after packing loss is closer to 28 / 58 / 68 m³ — the figures this calculator uses.
When is sea freight cheaper than air?+
As a rule of thumb, shipments over ~2 CBM or ~500 kg usually price better by sea LCL, but transit time is weeks instead of days. Compare your chargeable weight on the air freight calculator with the revenue tons here.