Start with the carrier and rate type
For inches and pounds, FedEx publishes a divisor of 139 for US, Puerto Rico, and international shipments. UPS publishes 139 for Daily Rates and 166 for Retail Rates. USPS examples use 166 when dimensional-weight eligibility applies. DHL Express commonly publishes 5,000 for centimetres and kilograms.
These are useful presets, not a promise that every shipment is billed that way. Contracted factors, product eligibility, cubic-volume thresholds, international lanes, and special services can change the applicable rule.
- Match the unit system to the divisor.
- Record service and rate type beside the result.
- Keep a custom-divisor option for contracted rules.
Calculate one parcel before the shipment total
Measure the finished outside length, width, and height. Multiply those dimensions and divide by the applicable factor. Compare that result with the actual packed weight, then apply the carrier's rounding rule. For multiple identical parcels, calculate the chargeable weight of one parcel consistently before multiplying by quantity unless the contract specifies shipment-level treatment.
A 20 × 16 × 12 inch parcel has 3,840 cubic inches. Dividing by 139 gives 27.63 lb; dividing by 166 gives 23.13 lb. A divisor choice can therefore change the planning result before rates or surcharges are applied.
Store the evidence used for a quote
Keep the carrier source or rate-card revision, the measured dimensions, actual weight, factor, rounding method, and calculation date. When an invoice differs, this record makes it possible to distinguish a measurement correction from a pricing-rule difference.
Working checklist
- ✓ Carrier and service
- ✓ Rate type
- ✓ Finished outside dimensions
- ✓ Actual weight
- ✓ DIM divisor
- ✓ Rounding and eligibility rule