Dimensional Weight Calculator

How to use

1. 1Pick a calculator mode: Forward to get the dim weight and billable weight from package dimensions, or Reverse to solve for the largest third dimension at a target weight.
2. 2Choose your carrier preset (UPS, FedEx, USPS Priority, DHL, Royal Mail, or Custom). The preset sets the imperial (in/lb) and metric (cm/kg) divisor used in the math.
3. 3Pick inches or centimeters for length and pounds or kilograms for weight. The result panel shows both unit systems, so you only need to type in the one you use day to day.
4. 4Enter length, width, height, and actual scale weight (or two known dimensions plus the target weight in reverse mode). The calculation updates on every keystroke.
5. 5Read the billable weight, dim weight, actual weight, girth, length-plus-girth, and carrier-rounded billable in the result panel. Use Copy summary to grab a full report for a ticket, invoice, or quote.

About this tool

Dimensional Weight Calculator turns the three sides of a package plus its actual scale weight into the dimensional weight, the billable weight, and the package girth that every carrier prices against. The math is the standard formula carriers publish: dimensional weight equals length times width times height divided by the carrier divisor, with the imperial divisor measured in cubic inches per pound and the metric divisor in cubic centimeters per kilogram. Billable weight is then the larger of dimensional weight and actual scale weight, since carriers pick the side that bills more. The tool ships with the published divisors for the major carriers (UPS US Domestic and International at 139 in/lb or 5000 cm/kg, FedEx US Domestic and International at the same 139 / 5000, USPS Priority Mail at the higher 166 in/lb divisor that applies to packages over one cubic foot shipping to zones five through nine, DHL Express at 139 / 5000, and the historic Royal Mail and Parcelforce 6000 cm/kg used by many UK couriers), plus a Custom mode for marketplaces, 3PLs, freight forwarders, and freshly published carrier rates. Pick inches and pounds for US workflows or centimeters and kilograms for EU and international rates; the result panel shows both unit systems regardless of which side you typed in, so you never need to switch tabs to confirm a metric quote. A reverse mode inverts the formula: enter two fixed dimensions plus the actual weight you want the carrier to bill at and the calculator returns the largest third dimension that keeps the parcel on the actual-weight side of the divisor. That is the answer to the question every ecommerce seller eventually asks, namely how much taller, longer, or wider a redesigned shipper can be before dim pricing kicks in. The tool also reports the package girth (two times width plus two times height) and the length-plus-girth total that defines the standard 165-inch UPS and FedEx Ground oversize threshold, plus the carrier-rounded billable weight (rounded up to the next whole pound or kilogram, the way carrier rating engines actually charge). Useful for Amazon FBA sellers and Shopify operators pricing shipping for new SKUs, packaging designers comparing box options before a redesign, freight planners checking IATA volumetric weight on air shipments, 3PL operators auditing carrier invoices for over-billed dim weight, mail rooms estimating retail shipping costs before they walk to the counter, and anyone who has asked why a low-density box cost so much to send. Everything runs locally in your browser using deterministic IEEE 754 arithmetic, so the dimensions, weights, and SKU data you type here never leave your device.

Free to use. Works in your browser. No signup, no login.