UNITS / M³ AND FT³
CBM to cubic feet (and back)
Cubic metres and cubic feet describe the same space; the factor between them is fixed by the definition of the foot. The mistakes happen around it: a rounded factor, a rounded carton, or a dimension converted twice.
Updated 28 October 2026 · figures from the linked sources or computed by the Livnaro calculator with the inputs shown
Where 35.3147 comes from
The foot is defined as exactly 0.3048 m (NIST SP 811), so a cubic foot is 0.3048³ = 0.028316846592 m³, exactly. Dividing 1 by that gives the familiar factor:
1 m³ = 1 ÷ 0.028316846592 = 35.314 666 7 ft³
ft³ = CBM × 35.3147 · CBM = ft³ ÷ 35.3147 (or × 0.0283168)
CBF and CFT both mean cubic feet. Packing lists and quotes may use either unit, so convert once, at the total.
Conversion table for freight
| What | m³ | ft³ |
|---|---|---|
| One 60 × 40 × 30 cm carton | 0.072 | 2.54 |
| One cubic metre | 1 | 35.31 |
| A typical LCL booking | 5 | 176.57 |
| 20' GP usable at 85% | 28.2 | 996 |
| 20' GP inside (SeaCube) | 33.2 | 1,172 |
| 40' GP usable at 85% | 57.6 | 2,033 |
| 40' GP inside (SeaCube) | 67.7 | 2,392 |
| 40' HQ inside (SeaCube) | 76.4 | 2,696 |
Container figures use the inside volume computed from the SeaCube inside dimensions (20', 40', 40' HC) and the 85% planning fill the calculator uses by default.
From inches, convert once
If the cartons are measured in inches, multiply the three inch figures and divide once. Converting each side to centimetres and rounding each one first adds error three times.
ft³ = L × W × H (in) ÷ 1,728 · m³ = L × W × H (in) ÷ 61,023.74
A 24 × 16 × 12 in carton is 4,608 in³: 2.667 ft³, or 0.07551 m³. Ten of them are 26.67 ft³ and 0.755 m³, which is what the calculator shows when field 1 is set to inches.
What rounding does to a full container
The factor is rarely the problem; rounding is. Two cases on a 40' HQ (76.4 m³ inside):
- Rounding the factor. 76.4 × 35.3147 = 2,698.0 ft³. With 35.3 it is 2,696.9 ft³ (−0.04%); with 35 it is 2,674 ft³ (−0.9%), about 24 ft³ or nine 24 × 16 × 12 in cartons that disappear on paper.
- Rounding each carton. A 24 × 16 × 12 in carton is 2.6667 ft³. Written as 2.67 ft³ and multiplied by 1,000 cartons, the list shows 2,670 ft³ instead of 2,666.7 ft³ (+0.12%). Rounded to 2.7 it shows 2,700 ft³ (+1.25%).
Keep the unrounded figure per carton and round only the shipment total, which is what the CBM calculator and its CSV export do.
Keep going
Guides
- How to calculate CBM for a shipmentCBM is length × width × height in metres, line by line.
- CBM to kg: the conversion carriers useThere is no physical CBM to kg conversion.
- How many pallets fit in a 40 ft containerFloor counts for EUR, 120 × 100 cm, 48 × 40 in and half pallets in 20ft, 40ft, 40HQ and 45HC containers, worked from inside dimensions, with clearance and double stacking.