Volume and weight GUIDE
Can you convert CBM to kg? Density and billable weight explained
Cubic metres measure volume; kilograms measure mass. Use density for physical weight and service rules for billable weight.
Calculate shipment volumeVolume and mass describe different things
CBM means cubic metres and measures occupied volume. Kilograms measure physical mass. There is no fixed conversion between them: a cubic metre of lightweight packaging and a cubic metre of dense goods can have very different weights.
If you already weighed the packed cartons, enter each carton’s actual weight and quantity in the mixed-carton calculator. It adds measured weights and volumes separately. Entering 0 for an unknown weight produces an incomplete weight total, not an estimate from volume.
Use density for physical mass
Mass (kg) = volume (m³) × density (kg/m³)
For a stated bulk density of 600 kg/m³, 2 m³ has a calculated mass of 2 × 600 = 1200 kg. A density of 100 kg/m³ would instead give 200 kg for the same volume. The density is an assumption or a measured property, not a number derived from CBM.
Choose the right volume and density. A solid-material density applies to solid material volume. A carton’s outside volume includes packaging and empty space; using solid-material density on that whole envelope can greatly overstate its mass. Bulk density can include voids, and the relevant packing condition must be stated.
The numerical example treats two 1 × 1 × 1 m units as 600 kg each. The tool’s independent totals are 2 m³ and 1,200 kg. It does not calculate or infer a product’s density.
Separate dimensional weight from actual weight
Dimensional or volumetric weight is a billing calculation, rather than a measurement of physical mass. For cm/kg and divisor 5,000, 1 m³ corresponds to 1,000,000 ÷ 5,000 = 200 kg raw dimensional weight. A different divisor changes that value.
This convention cannot prove that a 1 m³ parcel physically weighs 200 kg. Actual weight, dimension rounding and per-carton weight increments can change billable weight. The DIM calculator compares the larger of actual and dimensional weight under an editable per-carton rule; it is not a universal invoice formula.
Freight can use other billing conventions, chargeable units, minimums and contracts. A public “CBM to kg” factor may describe one pricing convention. Confirm its units, service and meaning before using it, and keep it separate from the cargo’s actual mass.
Use the right calculator for the question
| Question | Required information | Tool |
|---|---|---|
| What is the outside shipment volume? | Packed edges and carton counts | CBM calculator |
| What is the physical mass? | Measured packed weights, or relevant volume and known density | CBM totals measured weights only |
| What weight could a parcel be billed on? | Dimensions, actual weight, divisor and rounding | Dimensional-weight comparison |
| How many identical cartons fit? | Space, doors, orientation, height and payload | Pallet or container planner |
Use the DIM comparison to test a packaging change, or the container planner for a supported same-size carton arrangement. Confirm the carrier’s price separately; neither a volume total nor a weight convention is a rate quote.
Sources and scope
Official references checked 5 October 2026. Numerical tables are worked planning examples using the stated inputs; they are not carrier prices or loading certification.
- DHL Express India: measuring a packed box
External dimensions of a closed, packed carton; the 40 × 30 × 20 cm / 5,000 worked example.
- DHL: dimensional-weight formula
Compare actual and dimensional weight; published examples use 5,000 cm³/kg and 139 in³/lb. Check the applicable service's rounding separately.
Read our calculation methods and limitations. To report an error or a changed official rule, contact Freight Layout.
Use your own measurements
Put these steps to work with the free calculator. Check the applicable rules and equipment before using the result.
Calculate shipment volume