Size Calculations

Parcel companies use several different measurements when determining the size of your parcel.

Typically these are weight and dimensions including length, width and height. But carriers may also need to calculate girth and volumetric weight to account for overall size.

How girth is calculated

Girth is the measurement around the middle of your parcel. The calculation for girth is sometimes referred to more precisely as "girth plus length", and is as follows:

(sum of two smallest dimensions x 2) + longest dimension

For example, for a parcel measuring 20 x 30 x 40cm, the calculation would be:

(20+30) x 2 + 40 = 140cm

'Large package' and 'oversize' surcharges are often based on girth.

How volumetric weight is calculated

Volumetric weight is a measurement used by carriers to account for parcels that are light but very large.

If the volumetric weight is greater than the actual weight, it will be used to calculate the price of your shipment.

Volumetric weight is calculated by multipling the three dimensions of your parcel together and dividing by a number specified by the carrier.

This number, the 'divisor', will be provided in the service information for your chosen carrier. In this example, the divisor is 5000:

For the example in the first row, the shipment would be charged by the actual weight.

For the example in the second row, the shipment would be charged by the volumetric weight.