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Field note4 min read

How to Calculate FedEx Dimensional Weight

Work from finished outside dimensions to cubic size, DIM weight, and the greater billable weight.

FedEx formula

FedEx’s U.S. guidance publishes a 139 divisor for U.S., Puerto Rico, and international shipments. Verify the current Service Guide and your agreement.

FORMULA
FedEx DIM weight = L(in) × W(in) × H(in) ÷ 139

Example: 24 × 16 × 12 in

  • Cubic size: 4,608 in³.
  • 4,608 ÷ 139 = 33.15 lb.
  • Rounded dimensional weight: 34 lb.
  • At 18 lb actual, the DIM value is greater.