Dimensional Weight Calculator
Carriers charge large, light boxes by their size, not their weight. Enter your box dimensions and actual weight to see the dimensional weight and the weight you will be billed for.
Built and checked by Saurabh Pandey · page updated
Calculator
Fee breakdown
Enter the box dimensions.
How to use the Dimensional Weight Calculator
- Choose your carrier. Each one uses its own divisor, and USPS only applies dimensional weight to boxes larger than one cubic foot.
- Measure the box at its longest points, including any bulges, and round each side up to the next whole inch (or centimetre) as carriers do.
- Enter the actual weight of the packed box.
- Read the billable weight: the greater of the actual and dimensional weight, rounded the way the carrier rounds it.
How it is calculated
Dimensional weight (lb) = length × width × height (inches) ÷ divisor (139 or 166) Dimensional weight (kg) = length × width × height (cm) ÷ divisor (5,000 or 6,000) Billable weight = the greater of actual weight and dimensional weight
A 12 × 12 × 12 inch box has a volume of 1,728 cubic inches. With UPS daily rates or FedEx (divisor 139) that is 12.4 lb of dimensional weight, so a 5 lb box is billed as 13 lb. With USPS the same box is exactly one cubic foot, so it is billed by its actual weight.
Worked examples
A 12 × 12 × 12 in box weighing 5 lb with UPS
Dimensional weight 12.43 lb · Billable 13 lb · 5.9 kg · Charged by dimensional
The same box with USPS
USPS only uses dimensional weight above 1,728 cubic inches.
Dimensional weight 0 lb · Billable 5 lb · 2.27 kg · Charged by actual
A 16 × 14 × 10 in box weighing 4 lb with USPS
Dimensional weight 13.49 lb · Billable 14 lb · 6.35 kg · Charged by dimensional
A 30 × 20 × 20 cm parcel weighing 2 kg with DHL Express
DHL Express divides cubic centimetres by 5,000 and rounds up to the next half kilo.
Dimensional weight 5.29 lb · Billable 5.51 lb · 2.5 kg · Charged by dimensional
Fees used by this calculator
| Carrier | Imperial | Metric | Rule |
|---|---|---|---|
| UPS (daily rates) | L × W × H ÷ 139 (inches → lb) | ÷ 5,000 (cm → kg) | Rounded up to the next lb |
| UPS (retail rates) | L × W × H ÷ 166 (inches → lb) | ÷ 6,000 (cm → kg) | Rounded up to the next lb |
| FedEx | L × W × H ÷ 139 (inches → lb) | ÷ 5,000 (cm → kg) | Rounded up to the next lb |
| USPS (Priority, Ground Advantage) | L × W × H ÷ 166 (inches → lb) | ÷ 6,000 (cm → kg) | Rounded up to the next lb; only over 1 cubic foot |
| DHL Express (international) | L × W × H ÷ 139 (inches → lb) | ÷ 5,000 (cm → kg) | Rounded up to the next 0.5 kg |
| DHL eCommerce (US) | L × W × H ÷ 166 (inches → lb) | ÷ 6,000 (cm → kg) | Rounded up to the next lb |
| Amazon FBA fee tiers | L × W × H ÷ 139 (inches → lb) | ÷ 5,000 (cm → kg) | Not rounded |
Billable weight is the greater of actual and dimensional weight. USPS only applies dimensional weight to parcels larger than 1 cubic foot (1,728 cubic inches). Amazon assumes a minimum width and height of 2 inches for bulky items.
Last verified: . Official sources: UPS: shipping dimensions and weight · FedEx: what is dimensional weight? · USPS: parcel size, weight & fee standards · USPS Domestic Mail Manual 223 · DHL eCommerce: chargeable weight
How to avoid paying for air
- Use the smallest box that protects the item. Cutting one inch from each side of a 12-inch box reduces its volume by almost a quarter.
- Use mailers for soft goods. Clothing and textiles in poly mailers usually stay below the dimensional threshold.
- Keep a few box sizes. Matching box sizes to your common products avoids shipping small items in large boxes.
- Check Amazon's measurements. FBA fees for large standard and bulky items also use dimensional weight; an over-sized measurement can move an item into a more expensive tier.
Frequently asked questions
How do you calculate dimensional weight?
Multiply length × width × height in inches and divide by the carrier's divisor: 139 for UPS daily rates and FedEx, 166 for USPS and UPS retail rates. In centimetres, divide by 5,000 (or 6,000) to get kilograms.
What is the dimensional weight divisor for USPS?
USPS divides cubic inches by 166, and only for parcels larger than one cubic foot (1,728 cubic inches) sent with Priority Mail, Priority Mail Express, Ground Advantage or Parcel Select.
Is dimensional weight rounded?
UPS, FedEx and USPS round the result up to the next whole pound. DHL Express rounds up to the next half kilogram. Measure each side and round it up to the next whole inch or centimetre first.
What is billable weight?
The weight the carrier charges you for: the greater of the actual weight and the dimensional weight.
Does Amazon FBA use dimensional weight?
Yes. For large standard and bulky items Amazon uses the greater of the unit weight and the dimensional weight (volume ÷ 139), assuming a minimum width and height of 2 inches for bulky items.