How to Calculate Volumetric Weight for a Parcel
A parcel can weigh very little and still occupy a sizeable part of a delivery vehicle. Volumetric weight puts a weight figure on that space. To calculate it, multiply the packed parcel’s length, width and height, then convert the result using the factor specified for the delivery service.
Measure the finished parcel
Seal the parcel before taking any measurements. The box, cushioning and tape can affect its outside dimensions, while packaging adds to its actual weight. Measure the length, width and height across the outside, keeping a ruler or tape measure straight rather than following a crease or curve.
Look for parts that extend beyond the main shape. A bowed side or protruding flap can make a parcel wider than its flat panels suggest. For an irregular package, record its greatest extent in each direction and check the delivery service’s measurement instructions. A soft bag should be measured after filling and closing it, when its final shape is clear.
Put the sealed parcel on a scale and note its weight. Measuring and weighing the contents alone would leave you working with figures for something other than the parcel being sent.
Work through the calculation
Suppose the finished parcel measures 40 cm × 30 cm × 20 cm. Multiply the dimensions to find its volume:
40 × 30 × 20 = 24,000 cm³
Using an illustrative divisor of 5,000 cm³ per kg, divide the volume by that figure:
24,000 ÷ 5,000 = 4.8 kg
That is the parcel’s volumetric weight under the example factor. The divisor converts a measurement of space into a weight figure you can compare with the reading on a scale. The applicable factor depends on the delivery service.
Some formulas use metres and a multiplier instead. The same box occupies 0.024 m³. With the equivalent factor of 200 kg per m³, the calculation is 0.024 × 200 = 4.8 kg. Both routes produce the same answer because the units and factors have been converted together. Mixing a figure intended for centimetres with measurements in metres will give the wrong result.
Keep the outside measurements alongside your calculation. When looking for cheap parcel delivery, use the packed parcel’s dimensions and scale weight, not figures taken from a product listing.
Compare it with the weight on the scale
Imagine the example parcel weighs 2 kg when sealed. Its illustrative volumetric weight is 4.8 kg, so the volumetric figure is higher. On a service that bases its chargeable weight on the greater of actual and volumetric weight, the parcel’s size would govern that comparison.
Fill the same-sized box with something heavier and the result changes. At 6 kg on the scale, its actual weight exceeds the calculated 4.8 kg. The box takes up exactly as much room as before, but actual weight is now the larger figure.
Chargeable weight is a basis for assessing delivery, not a price. The service’s rules determine which figure is used and how it is rounded.
Check the service details before sending
Packaging is part of the calculation, but smaller is not automatically better. A box with a great deal of empty space increases the measured volume; removing cushioning that an item needs risks leaving it poorly protected. Choose packaging that fits the contents safely, then measure it as it will travel.
For the final calculation, use the chosen service’s factor and required units. Check its instructions for measurements between whole centimetres, weight rounding and irregular shapes. If the figure in a quote differs from your working, confirm the packed measurements and service factor before assuming the arithmetic is at fault.