A carton of pillows and a carton of steel hardware can weigh the same on your invoice and cost completely different amounts to ship. This is why — and how freight forwarders actually calculate what you owe.
Freight is never just "per kilo." Every shipment is measured two ways — how much space it takes up, and how much it weighs — and you're charged on whichever number is larger.
Sea freight is charged per CBM vs. weight-in-tons (roughly 1 CBM ≈ 1 tonne). Air freight uses the IATA volumetric divisor of 6000. Switch modes above to compare.
Based on a 20ft standard container (~33 m³ / ~28,200 kg payload) at realistic ~82% volume utilisation.
| Container | Volume capacity | Weight payload | Best for |
|---|---|---|---|
| 20ft Standard | ~33 m³ | ~28,200 kg | Dense, heavy goods — hardware, machinery parts |
| 40ft Standard | ~67 m³ | ~26,500 kg | Balanced general cargo |
| 40ft High Cube | ~76 m³ | ~26,000 kg | Bulky, lightweight goods — furniture, textiles, plastics |
Figures are standard industry approximations for illustration — your freight forwarder's booking confirmation is the authoritative number.
A carton of steel hardware and a carton of the same external dimensions filled with pillows can weigh wildly different amounts, but take up identical space. Freight forwarders don't charge by weight alone — for sea freight, they compare your total volume (in CBM) against your total weight (converted to tonnes, roughly 1:1 with CBM) and charge on whichever is greater. For air freight, the comparison is between actual weight and volumetric weight — a standardised conversion (L×W×H in cm, divided by 6000) that approximates how much space a light, bulky item takes up relative to a dense one. Bulky, lightweight products (think inflatables, lampshades, packaging-heavy items) routinely get charged on volume, not weight — which is exactly why a quote can come back higher than a simple per-kilo estimate suggested.
Read the full mechanics of freight mode selection in our complete import guide.
Send us your carton dimensions and weight — we'll get you a real LCL, FCL, or air quote, not an estimate.
