FedEx Volumetric Weight Calculator
Calculate FedEx dimensional weight and chargeable weight instantly — divisor 139 in³/lb (5,000 cm³/kg)
How FedEx Calculates Dimensional Weight
FedEx applies dimensional (DIM) weight pricing to FedEx Express, FedEx Ground and FedEx Home Delivery. The formula:
Dimensional Weight (lb) = Length × Width × Height (in) ÷ 139
In metric: Length × Width × Height (cm) ÷ 5,000 = dimensional weight in kg. FedEx bills the greater of actual and dimensional weight. The calculator above runs the comparison instantly and shows how DHL, UPS, USPS and others would bill the exact same box.
FedEx Billing Rules Worth Knowing
- Divisor 139 in³/lb everywhere: since January 2017, FedEx uses 139 for both US domestic (Ground and Express) and international shipments; the metric equivalent is 5,000 cm³/kg.
- Rounding: dimensions round to the nearest whole inch; final chargeable weight rounds up to the next whole pound (0.5 kg on metric international billing).
- FedEx One Rate skips DIM entirely: shipments in FedEx-provided One Rate packaging are flat-priced, no dimensional weight applies — often the cheapest route for small dense items up to 50 lb.
- Oversize thresholds: a package whose length exceeds 96 inches, or length + girth exceeds 130 inches, is billed at a 90 lb minimum plus oversize surcharges on Ground.
Worked Examples
Example 1: An e-commerce apparel box
Box: 16 × 12 × 6 in, actual weight 3 lb. Dimensional weight = 1,152 ÷ 139 = 8.3 lb → billed as 9 lb. Switching to a 15 × 11 × 3 in mailer-style box drops DIM weight to 3.6 lb → 4 lb, cutting the billed weight by more than half.
Example 2: An international sample shipment
Carton: 45 × 35 × 25 cm, actual weight 4 kg. Dimensional weight = 39,375 ÷ 5,000 = 7.9 kg → billed as 8 kg. The chargeable weight is double the scale weight, so quoting customers based on actual weight alone would underprice the shipment badly.
Example 3: When One Rate wins
A 12 kg (26 lb) box of machine parts fits a FedEx Medium Box. Weight-based Express billing might exceed $100 on many international lanes, while a domestic One Rate price is fixed regardless of weight up to 50 lb. For dense small shipments, always price the flat-rate option before defaulting to DIM pricing.
How to Pay Less on FedEx Shipments
Reduce the box before anything else, check One Rate for dense items, and compare carriers per shipment — with identical divisors, the real difference between FedEx, UPS and DHL comes from base rates, surcharges and your negotiated discount. See our FedEx vs UPS vs DHL comparison and the complete shipping cost guide for details.
What divisor does FedEx use for dimensional weight?+
FedEx uses 139 in³/lb for both US domestic and international shipments (5,000 cm³/kg in metric). This has applied to FedEx Express and FedEx Ground since January 2017.
How do I calculate FedEx dimensional weight?+
Multiply length × width × height in inches and divide by 139 for pounds, or measure in centimeters and divide by 5,000 for kilograms. FedEx bills the greater of this value and the actual weight.
Does FedEx One Rate use dimensional weight?+
No. FedEx One Rate shipments in FedEx-provided packaging are billed at a flat rate regardless of weight (up to 50 lb), making it a smart choice for small, dense items.
Does FedEx Ground apply dimensional weight to all packages?+
Yes. FedEx Ground applies the 139 in³/lb dimensional weight divisor to every package regardless of size. Whichever is greater — actual or dimensional weight — becomes the billable weight.
How does FedEx round dimensions and weight?+
FedEx rounds each dimension to the nearest whole inch before calculating, and rounds the final chargeable weight up to the next whole pound (or 0.5 kg for metric international billing).