Airfreight, Road transport and Courier services are charged per kilo.
However, if goods in relation to their weight occupy a lot of space, the charge will be over the volume weight. This is often the case for bicycles and furniture.

The carriers calculate over a volume ratio of 1 metric ton to 6, or 1000:6 = 166.66 kilo. This means that 167 kilo should not exceed the space of 1 cubic meter.

Example: a consignment of bicycles and furniture has an actual weight of 167 kilo and takes space for 1.73 cubic meter. Consequently the carrier will charge over: 1.73M3 x 166.66 = 288 kilo volume weight. So payment is over 288 kilo.
The carrier always charges over the highest of either the actual weight or the volume weight.