Dimensional Weight Calculator
A parcel’s billable weight: the greater of its actual weight and its size divided by your carrier’s divisor.
Result
Enter carrier’s dimensional divisor to see the result.
https://calcgallery.com/shopping/dimensional-weight-calculator/
Results are arithmetic from the amounts and rates you enter. The site publishes no tax rate, threshold or tipping convention, and rates vary by jurisdiction and change. Check the rate on your receipt, invoice or tax authority guidance, and confirm anything that matters with a qualified adviser. Read the full disclaimer
How to use the Dimensional Weight Calculator
- Measure the parcel’s length, width and height at their longest points, and weigh it.
- Enter the dimensional divisor from your carrier’s current service guide or rate card for the service you are using.
- Read the dimensional weight and the billable weight, the one the carrier charges on.
The formula
dimensional weight = length × width × height ÷ divisorbillable weight = the greater of the dimensional weight and the actual weightThe divisor is a volume per unit of weight. With 166 cubic inches per pound, every 166 cubic inches of box counts as a pound. Metric divisors such as 5,000 cm³/kg work the same way in centimetres and kilograms. The page converts whichever units you use, so an imperial box and a metric divisor still give the right answer. Make sure the divisor is in the unit selected beside it: 139 is a cubic-inches-per-pound figure, and entered as cm³/kg it makes a 50 × 40 × 40 cm box weigh 575.54 kg. The page warns when a divisor is far outside the usual range for its unit.
Measuring
Measure each side at its longest point, including any bulge. A box that is not rectangular is usually measured as the smallest rectangular box it would fit in. Your carrier’s guide says how it wants irregular items measured.
Keeping the charge down
Because the charge follows the volume, a box only slightly larger than its contents can cost noticeably more. Try the next box size down in the calculator to see what it would save.
With your numbers
- Volume = length × width × height = 8,400 in³
- Dimensional weight = 8,400 in³ ÷ 166 in³/lb = 50.6 lb
- Billable weight = the greater of that and 20 lb = 50.6 lb
Quick reference
Uses the divisor you enter. Carriers also round the measurements and the weight their own way, so a quote can differ slightly.
| Example | Billable weight |
|---|---|
| 21 × 20 × 20 in, 20 lb, divisor 166 | 50.6 lb |
| The same box, divisor 139 | 60.43 lb |
| 12 × 10 × 8 in, 15 lb, divisor 139 | 15 lb |
| 18 × 14 × 12 in, 6 lb, divisor 139 | 21.76 lb |
| 50 × 40 × 40 cm, 9 kg, divisor 5,000 | 16 kg |
| 30 × 20 × 10 cm, 4.2 kg, divisor 6,000 | 4.2 kg |
Common questions about the Dimensional Weight Calculator
- What is dimensional weight?
- A weight worked out from a parcel’s size rather than its scale weight. Carriers use it because a large, light box takes up as much room in a truck as a heavy one. They charge on whichever is greater, the dimensional weight or the actual weight.
- Where do I find the divisor?
- In your carrier’s service guide or rate card, often listed as the DIM divisor or DIM factor. It differs between carriers, between services and between retail and account rates, and carriers change it from time to time, so the site does not supply one. Imperial divisors are cubic inches per pound; metric ones are cubic centimetres per kilogram.
- How much difference does the divisor make?
- A lot. The same 21 × 20 × 20 in box has a dimensional weight of 50.60 lb at a divisor of 166 and 60.43 lb at 139, because a smaller divisor makes every box count as heavier.
- Why might my carrier’s figure differ slightly?
- Carriers may round the measurements to a whole inch or centimetre and round the weight up to a whole pound or kilogram, each in their own way, and some only apply dimensional weight above a certain size. This page shows the exact figures and the billable weight rounded up to a whole unit, so you can see both.