Free tool
CBM & Volumetric Weight Calculator
Calculate the total CBM, volumetric weight and chargeable weight of your cartons for sea, air or courier freight. See which measure you'll be billed on and estimate how many containers you need.
CBM & volumetric weight calculator
Work out the cubic metres and chargeable weight of your cartons so you know what your forwarder will actually bill — before you book sea, air or courier freight.
Enter your carton size, weight and quantity to see total CBM, volumetric weight and the chargeable weight your forwarder will bill.
Estimates only. Divisors and container capacities vary by carrier and service — always confirm the exact figures with your freight forwarder before booking.
How CBM and volumetric weight work
What is volumetric (dimensional) weight?
Light, bulky cartons take up space a carrier can't sell to anyone else, so freight is priced on whichever is greater: the actual weight or a volumetric weight derived from the size. For air and courier this is a weight in kilograms; for sea LCL it's the greater of your cubic metres (CBM) or your tonnes — the W/M, or weight-or-measure, rule.
The formulas
- CBM = (length × width × height in cm) ÷ 1,000,000 × number of cartons
- Volumetric weight (kg) = (length × width × height in cm) ÷ divisor × number of cartons
A 60 × 40 × 50 cm carton is 120,000 cm³ = 0.12 CBM. By air at the common 6,000 divisor that's 20 kg volumetric; if the carton actually weighs 12 kg you'll be billed on 20 kg, not 12.
Carriers and modes use different divisors
Air freight commonly uses 6,000 cm³/kg, express couriers often 5,000, and some consolidators 4,000 — a smaller divisor means a higher volumetric weight. Always confirm the divisor on your carrier's rate sheet; this tool lets you switch presets or enter a custom value.
Ways to reduce chargeable weight
- Right-size your cartons — trim empty headspace so volume tracks actual weight.
- Design flatter, denser packaging and remove void fill where it's safe to.
- Consolidate orders so cartons pack efficiently and hit better rate breaks.
- For bulky-but-light goods, compare sea LCL against air before you book.
CBM calculator FAQ
Multiply each carton's length, width and height in centimetres, divide by 1,000,000 to get cubic metres per carton, then multiply by the number of cartons. For example a 60 × 40 × 50 cm carton is 120,000 cm³, or 0.12 CBM each.
Volumetric weight converts a carton's size into a weight so carriers can price bulky but light shipments fairly. You're billed on whichever is greater — actual weight or volumetric weight — so a large, light parcel can cost more than its scale weight suggests.
It depends on the carrier and service. Air freight commonly uses 6,000 cm³/kg, express couriers often 5,000, and some consolidators 4,000. A smaller divisor means a higher chargeable weight, so always confirm the figure on your carrier's rate sheet. This tool lets you switch presets or enter a custom divisor.
Sea LCL uses the W/M (weight or measure) rule: you pay on the greater of your cubic metres or your weight in tonnes, per revenue ton. There's no volumetric divisor for sea — the calculator compares your CBM against your tonnes and shows which one applies.
Right-size your cartons to cut empty space, design flatter and denser packaging, and consolidate orders so cartons pack efficiently. For bulky but light goods it's also worth comparing sea LCL against air. Tasman's product development and packaging team can help optimise this.
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