What is a loading metre (LDM)?
LDM stands for "loading metre" and describes the length a shipment occupies in a standard road trailer. One LDM equals a floor area that is the full width of the trailer (around 2.40 m) by one metre of length. In road groupage (LTL) the freight rate is often based on the loading metres occupied rather than on weight or volume, because floor space is the real constraint inside a trailer.
How is LDM calculated?
The formula is:
LDM = (cargo width / trailer width) x cargo length x quantity
Trailer width is taken as 2.40 m by default, which is the usable internal width of tilt and reefer trailers. If the cargo spans the full width of the trailer, the ratio is 1 and the LDM equals the cargo length.
Example: four items 1.20 m wide and 0.80 m long, placed one behind the other: (1.20 / 2.40) x 0.80 x 4 = 1.6 LDM.
Standard internal vehicle dimensions
| Vehicle type | Length | Width | Height | Loading metres |
|---|---|---|---|---|
| Standard tilt trailer | 13.60 m | 2.45 m | 2.70 m | 13.6 |
| Mega tilt trailer | 13.60 m | 2.45 m | 3.00 m | 13.6 |
| Reefer | 13.30 m | 2.45 m | 2.60 m | 13.3 |
| Rigid truck | 7.20 m | 2.45 m | 2.45 m | 7.2 |
These figures reflect the vehicle classes commonly used in the market; internal dimensions vary by make and model by a few centimetres. The exact figures that apply to your shipment are confirmed at the quotation stage.
LDM, CBM and tonnes: which one is charged?
In groupage the carrier assesses all three measures and treats the highest as chargeable:
- Loading metres (LDM): the length occupied on the trailer floor. This is decisive for most shipments.
- Volume (CBM): matters most for non-stackable cargo.
- Weight (tonnes): comes into play for dense cargo such as metal, machinery or liquids.
Conversion assumptions widely used in the market: 1 LDM is roughly 1,750 kg, and for stackable cargo 1 LDM is roughly 1.8 CBM. For a non-stackable standard pallet most carriers apply a fixed 1 pallet = 0.4 LDM.
Common mistakes
- Using 2.50 m as the trailer width. The external width is 2.50 m; the usable internal width is around 2.40 m to 2.45 m.
- Counting only the floor area for non-stackable cargo. If nothing can be placed on top, the effective LDM rises.
- Ignoring pallet overhang. A few centimetres of overhang can block the next pallet row.
- Forgetting to multiply by quantity.
Groupage or full load?
Above roughly 6 to 7 LDM a full truck load (FTL) is often faster and cheaper than groupage. Below that figure, regular groupage transport (LTL) is the better fit. To compare the two, see the decision table on our international road transport page.
