CBM (cubic metre) is length × width × height in metres. For centimetres, multiply the three and divide by 1,000,000. A 20ft container holds about 33 CBM inside, with 25 to 33 CBM usable in practice. A 40ft holds about 67 CBM, with 55 to 67 usable. LCL sea freight is charged per CBM unless the cargo is very heavy.
Volume is the number every freight quote starts with. Get it wrong and the LCL invoice changes after the cargo is measured at the warehouse, the container you booked is too small, or you pay for a 40ft when a 20ft would have done. This guide covers the formula for every unit, how carriers turn volume into a charge, and how to choose a container size from your CBM.
The CBM Formula
| Your measurements are in | Formula for one carton |
|---|---|
| Metres | L × W × H |
| Centimetres | (L × W × H) ÷ 1,000,000 |
| Millimetres | (L × W × H) ÷ 1,000,000,000 |
| Inches | (L × W × H) ÷ 61,024 |
| Feet | (L × W × H) ÷ 35.315 |
Then multiply by the number of identical cartons and add up the different carton sizes. Always measure the outside of the packed carton at its widest points, including bulges, handles and pallet overhang. Carriers measure the same way.
Worked Examples
Example 1: Cartons
You have 40 cartons of 50 × 40 × 30 cm, each weighing 15 kg.
- One carton: 50 × 40 × 30 ÷ 1,000,000 = 0.06 CBM.
- Shipment: 0.06 × 40 = 2.4 CBM, with a total weight of 600 kg.
Example 2: Pallets
You have 6 pallets of 120 × 100 × 150 cm, including the pallet base.
- One pallet: 1.2 × 1.0 × 1.5 = 1.8 CBM.
- Shipment: 1.8 × 6 = 10.8 CBM.
Palletised cargo almost always has a higher CBM than the same cartons loose, because the pallet base and the gaps count. In return, it handles faster and is damaged less. If pallets cannot be stacked, the space above them is lost as well. Mark them “do not stack” only when you have to.
How Carriers Turn CBM into a Charge
Each mode converts volume into a chargeable unit in its own way. That is why the same cargo can be “light” by sea and “heavy” by air.
| Mode | Chargeable unit | Volume-to-weight ratio |
|---|---|---|
| Sea freight LCL | Revenue tonne (W/M): the greater of CBM or tonnes | 1 CBM = 1,000 kg |
| Sea freight FCL | Per container | Within the container’s payload limit |
| Air freight | Chargeable weight | 1 CBM ≈ 167 kg (divisor 6,000) |
| Lorry transport | Per trip, CBM, pallet, carton or kg | Depends on the lorry’s volume and payload |
In Example 1, the 2.4 CBM and 600 kg shipment pays for 2.4 revenue tonnes by LCL, because volume is the higher figure. By air, the same cargo has a volumetric weight of 2.4 × 167 = about 400 kg, so it would be charged on its actual 600 kg. Our air freight guide explains chargeable weight in detail.
Container Sizes and Real Capacity
| Container | Internal L × W × H (approx.) | Internal volume | Practical load | Max payload (approx.) |
|---|---|---|---|---|
| 20ft standard | 5.90 × 2.35 × 2.39 m | ~33 CBM | 25–33 CBM | ~28,000 kg |
| 40ft standard | 12.03 × 2.35 × 2.39 m | ~67 CBM | 55–67 CBM | ~26,500 kg |
| 40ft high cube | 12.03 × 2.35 × 2.69 m | ~76 CBM | 65–76 CBM | ~26,500 kg |
Exact figures vary by container owner, so check the tare and payload printed on the door. Two practical limits matter more than the brochure numbers:
- Stowage loss: irregular cartons, pallets and load-securing take space. Plan on 80–90% of the internal volume for mixed cargo.
- Road weight: a container can legally carry more than a prime mover may haul on some roads. Heavy cargo may “weigh out” before it “cubes out”, so check both.
Pallets per Container
| Pallet | 20ft (single tier) | 40ft (single tier) |
|---|---|---|
| Standard 1.2 × 1.0 m | 10 | 20–21 |
| Euro 1.2 × 0.8 m | 11 | 23–24 |
Double-stacking pallets doubles these numbers if the height and the pallet strength allow. A 20ft container has about 2.39 m of internal height, so two pallets of up to about 1.15 m each will fit.
From CBM to Container: Choosing the Right Size
| Total cargo volume | Usually the best option |
|---|---|
| Under about 13–15 CBM | LCL: you pay only for your CBM |
| About 15–28 CBM | 20ft FCL is often cheaper and faster than LCL |
| About 28–33 CBM | 20ft if it stows well, otherwise a 40ft |
| About 33–60 CBM | 40ft standard |
| Over about 60 CBM, or tall and light cargo | 40ft high cube |
The exact switch point between LCL and FCL depends on the current rates for your route. Our FCL vs LCL guide shows how to work out the break-even.
Common CBM Mistakes
- Measuring the product, not the carton: the carrier charges the packed outer dimensions.
- Forgetting the pallet: a pallet base adds about 0.15 m of height, plus any overhang.
- Rounding down: declare the true figure. Re-measurement at the warehouse is billed at the higher figure.
- Ignoring weight: heavy cargo such as tiles, metal parts and liquids can hit the payload limit long before the container is full.
- Mixing units: supplier specs in inches with a quote in centimetres is a classic source of errors.
Reducing CBM Without Damaging Cargo
- Right-size cartons to the product, and use flat-pack or nesting where the product allows.
- Build pallets to the full footprint without overhang, and to a stackable height.
- Consolidate small orders from the same supplier into one shipment.
- Load heavy, strong cartons at the bottom and use the full container height.
Shipping by CBM with De Hubs
De Hubs’ sea freight service runs FCL and LCL between West Malaysia and Sabah and Sarawak. FCL is priced per container and LCL per CBM, or per tonne for very heavy cargo. Send us the cargo type, weight, CBM, origin and destination, and we will recommend LCL, a 20ft or a 40ft and send a quotation. To see what else goes into the rate, read our guide to sea freight cost from West to East Malaysia.
Frequently Asked Questions
How do you calculate CBM?
Multiply length × width × height in metres. For measurements in centimetres, multiply the three and divide by 1,000,000. Multiply the result by the number of identical cartons to get the shipment’s total CBM.
How many CBM fit in a 20ft container?
A 20ft container has about 33 CBM of internal space, but cartons and pallets never pack perfectly. Plan on roughly 25 to 33 CBM of cargo depending on how well it stacks.
How many CBM fit in a 40ft container?
A standard 40ft container has about 67 CBM of internal space, and a 40ft high cube about 76 CBM. Realistic loads are around 55 to 67 CBM for a standard 40ft.
How is LCL charged: by CBM or by weight?
LCL is charged per revenue tonne, which is the greater of the volume in CBM and the weight in tonnes (1,000 kg = 1 tonne). Most cargo is charged on CBM. Very dense cargo is charged on weight.
How many pallets fit in a 20ft container?
Usually 10 standard 1.2 × 1.0 m pallets, or 11 Euro pallets (1.2 × 0.8 m), on the floor in a single tier. A 40ft takes about 20 to 21 standard pallets or 23 to 24 Euro pallets.