Many customers are surprised when a light parcel is charged at a higher weight. The reason is volumetric weight, also called dimensional weight. Aircraft space is limited by volume as well as weight, so carriers charge for whichever is greater.
The formula
For express courier services the usual formula is:
Length (cm) × Width (cm) × Height (cm) ÷ 5000 = volumetric weight in kg
Airline cargo commonly uses a divisor of 6000, and some economy services use other divisors. Always confirm the divisor for the service you book.
Chargeable weight
The chargeable weight is the higher of the actual weight and the volumetric weight. That figure is used to calculate your rate.
Example 1: a bulky box of clothes
A carton measures 60 × 40 × 40 cm and weighs 8 kg.
- Volumetric weight: 60 × 40 × 40 ÷ 5000 = 19.2 kg
- Actual weight: 8 kg
- Chargeable weight: 19.2 kg
Example 2: a compact, heavy box
A carton measures 30 × 30 × 20 cm and weighs 12 kg.
- Volumetric weight: 30 × 30 × 20 ÷ 5000 = 3.6 kg
- Actual weight: 12 kg
- Chargeable weight: 12 kg
How to reduce the chargeable weight
- Use the smallest suitable box. Every extra centimetre on each side adds volume quickly.
- Vacuum-pack soft items such as clothes, quilts and shawls.
- Avoid oversized outer cartons around already boxed products.
- Combine small parcels into one well-filled box rather than several half-empty ones.
- Ask about cargo services for heavier consignments, where the per-kilo rate can be lower.
Measure accurately
Measure the outside of the box at its longest points, including any bulges. Carriers re-measure every parcel, and a difference can lead to extra charges after shipping.
Our booking form calculates volumetric and chargeable weight automatically as you enter the dimensions. Ask us for a quote with your box size and we will advise the most economical option.