Work out how many cartons your order packs into, the volume (CBM) and total gross weight — the numbers a freight forwarder needs to quote ocean or air freight. Enter your own carton size and pack ratio: the maths is exact, but the figures are only as good as the pack spec you confirm at sampling.
⚠️ Indicative — confirm the pack spec at sampling. The maths is exact, but your real shipment depends on the final carton size, pack ratio and gross weight confirmed at sampling. Every carton — including a part-full last one — is counted as a full carton for volume and weight, which is how forwarders quote. Container-fill and W/M figures are standard planning references; confirm your actual CBM and chargeable weight with your freight forwarder before booking.
Before a factory ships, your order gets packed into export cartons — and your freight forwarder quotes off three numbers: how many cartons there are, how much volume they take up (CBM), and how much they weigh. This tool turns your pack spec into all three, so you can budget freight and sense-check whether the order fits an LCL consignment or a full container.
Enter your total units, how many pieces go in each carton, the carton's length × width × height in centimetres, and its gross (packed) weight. Everything updates as you type.
Nothing here is hidden or invented. The exact maths is:
Cartons = total units ÷ units per carton, rounded up
CBM per carton = (L × W × H in cm) ÷ 1,000,000
Total CBM = CBM per carton × cartons
Total gross weight = carton gross weight × cartons
Worked example (the default values): 1,000 units at 50 per carton is 20 cartons. A 60 × 40 × 40 cm carton is 0.096 CBM, so 20 cartons is 1.92 CBM total. At 12 kg per carton, that's 240 kg gross. Change any input and the numbers follow.
Less-than-container-load (LCL) sea freight is billed on "weight or measure" (W/M) — the carrier charges whichever is greater between your total CBM and your weight in tonnes, treating 1 CBM as 1,000 kg. Knitwear is light and bulky, so a shipment almost always prices out on volume, not actual kilos. That's why the CBM figure is the one to watch. A full container (FCL) is charged flat per box instead, so once your total CBM approaches roughly 28 (20ft) or 58 (40ft), it's worth pricing FCL against LCL.
CBM (cubic metres) per carton is length × width × height in centimetres, divided by 1,000,000. Multiply that by the number of cartons for your total volume. The number of cartons is your total units divided by the units packed per carton, always rounded up — a part-full carton still takes a full carton's space on the vessel.
LCL sea freight is billed on "weight or measure" (W/M): the carrier charges whichever is greater between your total CBM and your weight in tonnes, where 1 CBM is treated as 1,000 kg. Knitwear is light and bulky, so it is almost always charged on volume (CBM), not actual weight. A full container (FCL) is charged as a flat rate per container instead.
As a practical loading guide, you can usually fit about 28 CBM in a 20ft container, about 58 CBM in a 40ft, and about 68 CBM in a 40ft high-cube. Divide your total CBM by these to estimate container fill. Real capacity depends on your carton dimensions and how cleanly they stack — odd sizes leave dead space.
Use your own figures from the factory. At Kiwi Giyim we confirm the exact carton dimensions, gross weight and pack ratio (for example 50 pieces per export carton, one colour or assorted sizes) at the sampling stage, and export cartons are typically double-wall corrugated. Until you have those numbers, enter a realistic estimate — this tool only does maths on the values you give it.
Related free tools: Knitwear Cost Calculator, Size Run Calculator and Yarn Count Converter — or head back to the US knitwear hub to see the full manufacturing picture.