FedEx charges on the dimensional weight or the actual weight of a package, whichever is greater, and it uses a single divisor for United States parcels: dividing by 139, with each measurement rounded to the nearest whole inch (per fedex.com, checked 2026-07-28). There is no cubic-foot threshold to duck under, so the rule reaches small boxes as readily as large ones.
FedEx runs both numbers on every shipment and keeps the bigger one, so the tape measure deserves as much respect as the scale.
Read from the FedEx packaging page on dimensional weight, 2026-07-28. We are quoting rather than paraphrasing because the summaries floating around disagree with each other.
The same 5 lb of household goods, packed three ways, quoted from Newark, NJ 07102 to Atlanta, GA 30303 on 2026-07-28. Each quote returned five rates and we are reporting the FedEx rows exactly as they came back.
| Carton | Cubic inches | Size weight at 139 | FedEx Ground Economy | FedEx Ground |
|---|---|---|---|---|
| 12 x 10 x 6 in | 720 | 6 lb | $14.31 6-7 business days | not among the five rates returned |
| 18 x 14 x 10 in | 2,520 | 19 lb | $20.51 6-7 business days | $32.23 5-6 business days |
| 24 x 18 x 14 in | 6,048 | 44 lb | $45.51 6-7 business days | $59.61 5-6 business days |
Ground Economy more than tripled, from $14.31 to $45.51, while the contents stayed at 5 lb. On the two cartons where FedEx Ground also appeared, the step up to the faster service cost $11.72 on the middle carton and $14.10 on the largest, and it bought one business day off each end of the window. The smallest carton returned no FedEx Ground row at all in that capture, so the cell above says so rather than guessing at a figure.
FedEx applies an Oversize charge to packages that exceed 96 inches in length or 130 inches in length and girth, bills them on the greater of rounded actual or dimensional weight, and sets a 90 lb minimum billable weight. The 2026 US package services amounts are $255.00 in zone 2, $275.00 in zones 3 and 4, and $320.00 in zones 5 and 6 (FedEx 2026 surcharge and fee changes, effective January 5, 2026).
FedEx states that when a package qualifies for more than one of Additional Handling by dimension, packaging or weight, the Oversize charge or an unauthorized package charge, only the highest of them applies after discounts. Stacking is not how that table works.
FedEx publishes Additional Handling in three flavours with 2026 amounts attached, but the United States page listing the inch and pound triggers was unreachable when we checked on 2026-07-28. We are not going to print a threshold we could not read, so this page stays quiet on it.
FedEx publishes a single figure for this market: divide length by width by height in inches, then by 139. Its packaging page, read 2026-07-28, phrases it as dividing by 139 for U.S., Puerto Rico, and international shipments.
The FedEx page we read gives one divisor for United States shipments and draws no line between the two service families. If a rate agreement changes that for a particular account, it would come from the agreement rather than from the published rule.
Round each measurement to the nearest whole inch before multiplying, per the FedEx instruction. The comparison that follows is simple: FedEx charges on the dimensional weight or the actual weight, whichever is greater.
Holding contents at 5 lb on the Newark to Atlanta lane on 2026-07-28, FedEx Ground Economy quoted $14.31 for a 12 x 10 x 6 in carton, $20.51 for an 18 x 14 x 10 in one and $45.51 for a 24 x 18 x 14 in one. The scale never changed.