CBM Calculator — Cubic Metres

Freight is bought by volume, and the world’s volume currency is the cubic metre — CBM. Enter a box’s length, width and height in whatever unit your tape measure speaks, add the quantity, and this calculator returns the CBM per piece, the total CBM, and the cubic-feet equivalent the North American carriers will quote against it.

One Multiplication, Priced in Metres

CBM is the least mysterious unit in logistics: length × width × height, in metres, full stop. The craft lies entirely in the conversions and the measuring conventions. In centimetres — the unit of most packing lists — the product is divided by 1,000,000 (100³, a divisor worth memorising, since a slipped zero in it is a tenfold freight bill). Carriers measure the outermost dimensions of the piece as presented: pallet included if palletised, bulges and bowed carton walls included, which is why the calculator's note counsels rounding up. Mixed shipments are summed piece-wise — CBM is additive across unlike boxes in a way that stacking efficiency is not, a distinction the container figures in the note handle: the rated 33 CBM of a 20-foot container is geometry; the 25–28 that load in practice is geometry minus the voids no arrangement of rectangular boxes can fill.

Worked Example: Fifty Cartons to the Port

The defaults price a standard export run: cartons of 120 × 80 × 60 cm, fifty of them. Each: 1.2 × 0.8 × 0.6 = 0.576 CBM. Total: 0.576 × 50 = 28.8 CBM — which the note's container figures immediately interpret: too much for one practically-loaded 20-foot container, a comfortable half of a 40-foot, or an LCL (less-than-container-load) booking priced per CBM against the shipment's weight in revenue tons. In cubic feet the same consignment is about 1,017 ft³. Notice how the single multiplication cascades into routing decisions; this is why CBM, and not weight, is the first number every freight quote asks for and why getting it right — outermost dimensions, honest rounding — is the cheapest accuracy in the entire shipping process.

CBM, Weight, and the Revenue Ton

Volume's rival is mass, and carriers charge for whichever is greater — the revenue (or chargeable) ton convention: one revenue ton is 1 CBM or 1,000 kg, carrier's choice by arithmetic. A shipment of pillows at 28.8 CBM and 900 kg bills as 28.8 revenue tons; the same volume of steel parts at 9,000 kg bills as 9. Air freight runs the identical contest in different dress (the dimensional weight of the neighbouring calculator, divisor 6,000 cm³/kg in its classic form). Knowing your CBM and your gross weight side by side — and therefore which side of the contest you lose — is the shipper's basic literacy, and it decides packaging redesigns: compressing a product's carton by 20% is a 20% freight cut exactly when volume, not weight, was doing the billing.

Estimating Before Anything Is Packed

Most CBM questions arrive earlier than the cartons do — at the purchase order, the product design, the warehouse plan — and the estimation discipline differs from measurement in one respect: it must price the packed state from the bare product. The working method is to add the packaging's allowance to each dimension (carton walls, cushioning, the retail box's vanity) before multiplying, and to sanity-check the result against the product's own volume: a packed CBM per unit that is less than about 1.3 times the product's bounding volume is a fantasy that the freight invoice will correct. Warehouse planners run the same numbers for racking (a standard pallet position holds roughly 1.0–1.44 CBM of stacked cartons depending on height discipline), which is why this one multiplication quietly sizes buildings as well as bills.

CBM in the Warehouse: The Same Number, Standing Still

Freight's unit moonlights as storage's unit, and the warehouse version of the discipline is worth its paragraph: racking, shelf bins and cold rooms are all bought and billed by the cubic metre they can hold, and stock is profiled by the CBM it occupies per unit of sales velocity — the "cube" of warehouse slotting. A slow product in a bulky carton is a rent problem before it is a sales problem, which is why the calculator's per-piece figure, multiplied by stock on hand, appears in inventory reviews far from any port. The measurement conventions stay mercifully identical (outer dimensions, honest rounding), making CBM one of the few numbers a business computes once and spends in three departments — purchasing, logistics and facilities — without translation.

Air Cargo Speaks CBM Too, With an Accent

Airlines quote volume in the same cubic metres with a stowage twist: cargo holds are curved, and the effective CBM of a lower-deck position is less than its rectangular measure, which is why air waybills and the dimensional-weight system do most of the practical pricing work and CBM serves as the planning unit rather than the billing one. The shipper's takeaway is modest and useful: compute the CBM once, with this page's outermost-dimensions discipline, and it serves the sea quote exactly, the air quote approximately, and the warehouse precisely — a rare example of one number surviving three industries' dialects with only its interpretation, never its value, in dispute.

Reading a Freight Quote Backwards

The invoice's CBM line deserves the same audit as any multiplication with money attached: carriers and forwarders re-measure, and their figure displaces yours where they differ, so the shipper's habit is to recompute the quote from the carrier's own stated dimensions before paying — discrepancies are usually honest (a bulged carton measured at its proudest point, a pallet you forgot you requested) and occasionally systematic (a dimensioner's calibration, a rounding convention quietly applied per piece instead of per shipment). Ten minutes with this calculator against the quote's dimensions is the cheapest audit in logistics, and forwarders expect it: a customer who recomputes is a customer whose next quote arrives pre-audited by caution.

Related Tools

More from the Other Calculators hub: the Dimensional Weight Calculator — volume priced as kilograms — and the Tank Volume Calculator for liquids that refuse to be boxes.

Frequently Asked Questions

How do I calculate CBM from centimetres?

Multiply length × width × height in centimetres and divide by 1,000,000 — or convert each side to metres first (divide by 100) and multiply, which is what this calculator does internally. The worked example's carton: 120 × 80 × 60 = 576,000 cm³ ÷ 1,000,000 = 0.576 CBM. The divisor is a million because volume scales with the cube of length: 100 cm to the metre, cubed. Most CBM errors in the wild are this divisor carrying the wrong number of zeros, which is the practical argument for letting the calculator hold it.

How many CBM fit in a shipping container?

Nominal internal volumes: about 33 CBM (20 ft), 67 CBM (40 ft) and 76 CBM (40 ft high-cube). Practical loading achieves roughly 80–85% of nominal with mixed cartons — the note's 25–28 and 55–60 figures — because boxes never tessellate perfectly and access, weight distribution and securing all consume space. Uniform, stackable cartons sized to the container's internal dimensions approach the nominal figure, which is why export packaging is so often designed backwards from the box the boxes must fill.

What is the difference between CBM and cubic feet?

The same volume in different dialects: 1 CBM = 35.3147 cubic feet, and the calculator prints both on one line. Ocean freight's global convention is metric (CBM); North American domestic trucking and warehousing often quote cubic feet; air freight works in kilograms (via dimensional weight) with cm³ underneath. Converting faithfully — and never confusing ft³ with CBM in a quote, a 35-fold misunderstanding — is the whole skill, and it is mechanical enough to delegate to this page permanently.

Should I include the pallet in the measurements?

If the goods travel palletised, yes — the carrier charges for the space the shipment occupies as tendered, pallet footprint and height included (a standard pallet adds roughly 0.1–0.15 CBM of footprint-height product at typical stack heights, and its own 15 cm of height to every stack). Measure after palletising and wrapping, at the wrap's outermost faces. Quoting from the bare cartons and shipping the pallet is the classic way to receive a corrected invoice larger than the quote.

How is CBM used for moving house?

Movers estimate household volume in CBM or cubic feet from an inventory (a typical 1-bedroom flat runs very roughly 8–12 CBM of packed goods; a family house 25–40), price the move on it, and reconcile against the loaded truck. The calculator prices the measurable part — boxed and furniture items by their outer dimensions — while the estimator's art is the allowance for the un-boxable. For self-moves, the same total sizes the truck or storage unit, with the container section's 80% rule applying to vans and units alike.

What about irregular shapes — cylinders, furniture, vehicles?

Carriers price the bounding box: the smallest rectangular box the item fits in, by outermost points (a bicycle ships as its length × handlebar width × height, not its graceful actual volume). This calculator therefore prices irregular freight correctly if you enter the bounding dimensions — which is also the honest way to compare quotes, since every carrier in the chain will measure it the same unromantic way. Genuinely cylindrical cargo (rolls, drums) is sometimes rated on its true cylinder volume by agreement; absent that agreement, the box rules.