CBM to CFT Conversion for Shipping (Table + Formula)

Ocean docs use CBM (cubic meters). US domestic logistics — LTL carriers, warehouses, storage pricing — use CFT (cubic feet). Cross-border cargo forces the conversion on you constantly. Below: the exact factor, reference tables, the shortcuts worth memorizing, and where the math quietly goes wrong.

The Factor: 1 CBM = 35.315 CFT

1 CBM = 35.3147 CFT and 1 CFT = 0.0283168 CBM. For freight, 35.315 is precise enough everywhere:

CFT = CBM × 35.315 · CBM = CFT ÷ 35.315

Example: 2.4 CBM × 35.315 = 84.76 CFT. Reverse it: 120 CFT ÷ 35.315 = 3.40 CBM.

Quick Conversion Table

Container rows use the internal volumes standardized under ISO 668, the series that fixes container dimensions worldwide — full internal measurements sit on the container dimensions guide. These are nominal volumes. Real cartons stow meaningfully less, as covered in how many CBM fit per container.

Convert in Your Head

Four decimals rarely matter on a warehouse floor or a phone call. You need an answer right to within a percent. Three anchors carry it:

• CBM to CFT: multiply by 35, add 1%. 12 CBM × 35 = 420, plus 1% ≈ 424 CFT. Exact is 423.8 — close enough to sanity-check any invoice on the spot.

• CFT to CBM: drop two digits, multiply by ~2.8. Anchor on 100 CFT ≈ 2.83 CBM; 750 CFT is then about 7.5 × 2.83 ≈ 21.2 CBM (exact: 21.24).

• Container sanity anchors. A 20ft is roughly 1,170 CFT nominal, a 40ft roughly 2,390, a 40HC roughly 2,700. If a converted figure implies more cargo than the container physically holds, the conversion — or the packing list — is wrong.

Use the shortcuts to catch errors. Use the exact 35.315 factor for anything that lands on paper: quotes, invoices, customs entries, density declarations.

CFT Straight From Inches

Dimensions already in inches? Skip the meter step: CFT = (L in × W in × H in) ÷ 1,728 — 1,728 is 12³, the cubic inches in a cubic foot.

Example: a 48 × 40 × 60 in palletized shipment = 115,200 in³ ÷ 1,728 = 66.67 CFT = 1.89 CBM. That inch-based CFT number feeds freight density (lb/ft³) directly for US LTL class calculation — see how to calculate freight density.

Which Unit, Which Context

Air freight is the outlier. The IATA volumetric convention divides cubic centimeters by 6,000 for a chargeable kilogram, so neither CBM nor CFT hits the invoice directly — though both are one multiplication from the same cm³ total.

Typical workflow: your supplier's packing list says 8.5 CBM; your US warehouse quotes storage at $0.55/CFT/month. 8.5 × 35.315 = 300.2 CFT → about $165/month. The CBM calculator outputs both units side by side for every line item, so mixed workflows skip the separate conversion step.

Where the Conversion Breaks

• Using 35 instead of 35.315. The shortcut understates CFT by about 0.9%. On a storage bill that is pocket change. On an LTL density sitting just above a class break it decides whether you keep the class you declared or take the one the carrier's re-measure assigns — and reclass fees typically cost more than the original rate difference.

• Multiplying when you should divide. One-second check: the CFT figure must always run roughly 35 times the CBM figure. If your "conversion" shrank the number going CBM to CFT, the factor went the wrong way.

• Converting rounded per-carton figures, then multiplying by count. A packing list showing 0.10 CBM per carton (rounded from 0.099) converts to a total that drifts several CFT from reality across hundreds of cartons. Convert the exact total, not the rounded lines.

• Confusing CFT with the measurement ton. Some older ocean tariffs and port charge schedules still quote a "measurement ton" or "freight ton" — a legacy unit equal to 40 CFT (about 1.133 CBM). A charge "per ton" there is neither a metric tonne nor a CFT; misreading it typically misestimates the charge by an order of magnitude.

Precision Notes

• Convert the total, not each line, when you only need the total — per-line rounding then summing drifts.

• CFT figures in US LTL are usually rounded to one decimal; CBM in ocean docs to two or three decimals.

• Check whether a "cft" figure on an invoice is per piece or total — loose labeling causes real billing disputes.

• Volumes converted for chargeable-weight purposes go through cm³, not CFT — if a quote involves air or express, work in metric from the start and convert to CFT only for the US domestic legs. What CBM itself represents, and how it is measured, is covered in what is CBM.

One Shipment, Three Invoices: Ningbo to Long Beach

Watch the conversion do real work across a shipment's life. An importer of kitchenware books 250 cartons out of Ningbo, each 55 × 45 × 40 cm at 12 kg. The supplier's packing list and the ocean quote both speak metric: 0.099 CBM per carton, 24.75 CBM and 3,000 kg total ( open this shipment in the CBM calculator to see both units computed per line).

The moment the goods clear customs in Long Beach, the units flip. The receiving 3PL bills storage per cubic foot: 24.75 × 35.315 = 874.0 CFT, so at an illustrative $0.50/CFT/month the pallet positions cost about $437 a month. Then a portion moves onward to a retailer by LTL, and the trucking quote needs density in pounds per cubic foot: 3,000 kg is about 6,614 lb, and 6,614 ÷ 874 ≈ 7.6 lb/ft³ — which lands in the class 125 band of the NMFC freight class chart. One shipment, three invoices, every one the same physical volume through a different unit. A conversion error at any step is not small — it produces a wrong storage accrual or a misdeclared freight class, and reclassification fees on the LTL leg.

So experienced import teams convert once, at the total level, and carry both figures on the internal shipment record from day one rather than re-deriving CFT every time a US invoice arrives.