FedEx Dimensional Weight Calculator
See how FedEx bills your package: DIM weight with the official 139 divisor, billable weight, and the Additional Handling and Oversize thresholds FedEx applies to US domestic shipments.
What this means
FedEx computes DIM weight as length × width × height ÷ 139 (inches and pounds). Every fractional inch rounds UP to the next whole inch — 47.1 in becomes 48 in — and the result rounds up to the next whole pound. Billable weight is the greater of the rounded actual weight and the DIM weight.
FedEx surcharge diagnostics
The result below also checks FedEx's deterministic surcharge thresholds: Additional Handling applies when the longest side exceeds 48 in, the second-longest side exceeds 30 in, length + girth exceeds 105 in, or cubic volume exceeds 10,368 in³ (new in January 2026). Packages triggering Additional Handling–Dimension carry a 40-lb minimum billable weight. Oversize applies above 96 in length, 130 in length + girth, 17,280 in³, or 110 lb. Ground packages over the maximum limits (108 in / 165 in / 150 lb) incur the Unauthorized Package Charge with a 90-lb minimum billable weight.
Worked example
24 × 18 × 12 in = 5,184 in³ ÷ 139 = 37.3 → 38 lb DIM weight. At 8 lb actual weight, FedEx bills 38 lb (+375%). Shrink the box to 20 × 16 × 10 in and the same package bills 24 lb.
Potential action
If DIM weight is driving the bill, use the box size optimizer. If the package is near a surcharge threshold, the surcharge checker shows how far each threshold is.