Dimensional Weight Calculator
The DIM weight and billable weight carriers use to price your shipment
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Quick summary
Enter your package's length, width, height, and actual weight, plus the carrier's DIM divisor (139 for US domestic, 166 international), to find the dimensional weight and the billable weight — the greater of the two. A 20×15×10-inch box (3,000 in³) has a dimensional weight of 22 lbs at divisor 139, so even if it weighs 8 lbs, you're billed for 22. Large, light packages are billed by size — right-sizing the box is the main way to cut the charge.
Reviewed by Simple Calculators TeamLast reviewed
How to use this calculator
- Enter the inputs requested by the calculator.
- Choose the units or options that match your situation and review the assumptions.
- Run or update the calculation to see the result.
- Review the result, breakdown, and formulas shown on the page.
- Check the inputs, units, dates, and limitations before saving or sharing the result.
Frequently asked questions
What is dimensional weight?
Dimensional (or volumetric) weight prices a package by the space it occupies rather than its actual weight. It's length × width × height ÷ a divisor (139 for US domestic ground/air). Carriers bill the greater of dimensional and actual weight, so bulky-but-light shipments cost more than their scale weight suggests.
How do I calculate billable weight?
Compute dimensional weight (L × W × H ÷ divisor, rounded up), compare it to the actual weight (also rounded up), and take the larger. That's your billable weight. This calculator does both and tells you which one you're billed on.
What is the DIM divisor and which should I use?
The DIM divisor converts cubic inches to pounds. Common US values are 139 for domestic FedEx/UPS ground and air and 166 for international; some services and postal options differ. A larger divisor yields a lower dimensional weight. Check your specific carrier and service contract for the exact figure.
How can I reduce dimensional weight charges?
Use the smallest box that safely fits the contents — excess air is what inflates dimensional weight. Cutting each dimension even slightly can drop you below the actual weight so you're billed on the (lower) scale weight instead. Custom-sized or right-sized packaging is the standard fix for shippers.
Key terms
- Dimensional Weight
- Weight based on volume: L × W × H ÷ divisor; what bulky-light parcels are billed on.
- Billable Weight
- The greater of dimensional and actual weight; what the carrier charges.
- DIM Divisor
- The constant (e.g. 139) converting cubic inches to dimensional pounds.
Methodology, sources & limitations
This page shows the formula, assumptions, and limitations used for this estimate. Rates, thresholds, and other time-sensitive inputs can change, so verify them against the relevant official source before relying on a result.
For our review approach and the primary sources we consult, see the methodology and source policy. If you spot an outdated figure or formula, please contact us with a correction.