Between 10 and 20 lb on the short lane. Between 4 and 10 lb on the long one.
Five cartons into Ohio
Each request went out with one carton and came back with the five least expensive rates available for it. The columns below pull out the cheapest postal row and the cheapest FedEx row from each of those answers, so the comparison is like for like on the same box, the same day and the same address pair.
| Carton | USPS | FedEx | Lower price |
|---|---|---|---|
| 10 × 7 × 4 in 1 lb | $9.47 USPS Ground Advantage, 2-3 business days | no FedEx row among the five returned | USPS |
| 12 × 10 × 6 in 4 lb | $8.42 USPS Ground Advantage, 2-3 business days | $11.78 FedEx Ground Economy, 5-6 business days | USPS |
| 16 × 12 × 9 in 10 lb | $13.88 USPS Ground Advantage, 2-3 business days | $16.31 FedEx Ground Economy, 5-6 business days | USPS |
| 18 × 14 × 12 in 20 lb | $28.41 USPS Ground Advantage, 2-3 business days | $19.70 FedEx Ground Economy, 5-6 business days | FedEx |
| 20 × 16 × 14 in 45 lb | no postal row among the five returned | $46.83 FedEx Ground Economy, 5-6 business days | FedEx |
The lead changes hands once, somewhere between the 10 lb carton and the 20 lb carton. Below that line the postal price is the one to beat; above it the postal price climbs faster than the FedEx price does, and at 45 lb no postal row made the shortlist at all. The faster FedEx tier turned up on that heavy carton too, at $52.04 for FedEx Ground with a 4-5 business day window.
The same cartons, sent much further
Distance does not shift both carriers by the same amount, so the crossover is not a fixed weight. Running four of the five boxes out to Phoenix moved it down the ladder by a full step.
| Carton | USPS | FedEx | Lower price |
|---|---|---|---|
| 10 × 7 × 4 in 1 lb | $11.12 USPS Ground Advantage, 4-5 business days | no FedEx row among the five returned | USPS |
| 12 × 10 × 6 in 4 lb | $14.70 USPS Ground Advantage, 4-5 business days | no FedEx row among the five returned | USPS |
| 16 × 12 × 9 in 10 lb | $25.18 USPS Ground Advantage, 4-5 business days | $23.92 FedEx Ground Economy, 9-10 business days | FedEx |
| 18 × 14 × 12 in 20 lb | $58.70 USPS Ground Advantage, 4-5 business days | $36.63 FedEx Ground Economy, 9-10 business days | FedEx |
On the Ohio lane the postal service was still ahead at 10 lb. On the Arizona lane it had already fallen behind at that weight, and by 20 lb it was quoting more than half again what FedEx wanted. Anyone who has memorized a rule of thumb from one favorite lane should retest it on the route actually in front of them.
One more row from the Arizona capture is worth keeping: the faster FedEx tier, FedEx Ground, quoted $58.63 on that 20 lb carton with a 6-7 business day window. That sits seven cents under the postal price and arrives two business days later, which is the sort of near-tie that makes the delivery window the real tiebreaker rather than the number.
Quote your carton on your own lane Add UPS to the comparison
The crossover moves with the lane, not just the weight
The two lanes above show FedEx pulling ahead at a heavier weight on the longer haul than on the shorter one. A wider check — eight destinations out of Newark, NJ 07102 at 1, 5, 20 and 50 lb, quoted 2026-08-23 — shows the crossover is not one number even within the same rough distance band. It depends on the specific lane.
| Destination | USPS | FedEx | Lower price |
|---|---|---|---|
| Hoboken, NJ 07030 | $10.43 USPS Ground Advantage, 3-4 business days | $11.42 FedEx Ground Economy, 1 business day | USPS |
| Philadelphia, PA 19102 | $13.68 USPS Priority Mail, 2-3 business days | $11.42 FedEx Ground Economy, 2-3 business days | FedEx |
| Atlanta, GA 30303 | $14.02 USPS Ground Advantage, 4-5 business days | $14.31 FedEx Ground Economy, 4-5 business days | USPS |
| Chicago, IL 60601 | $14.02 USPS Ground Advantage, 7-8 business days | $17.61 FedEx Ground Economy, 3-4 business days | USPS |
| Dallas, TX 75201 | $16.00 USPS Ground Advantage, 4-5 business days | $16.22 FedEx Ground Economy, 4-5 business days | USPS |
| Denver, CO 80202 | $16.97 USPS Ground Advantage, 5-6 business days | $17.52 FedEx Ground Economy, 5-6 business days | USPS |
| Los Angeles, CA 90011 | $19.64 USPS Ground Advantage, 5-6 business days | $20.50 FedEx Ground Economy, 7-8 business days | USPS |
| Seattle, WA 98101 | $19.64 USPS Ground Advantage, 7-8 business days | $20.50 FedEx Ground Economy, 8-9 business days | USPS |
| Destination | USPS | FedEx | Lower price |
|---|---|---|---|
| Hoboken, NJ 07030 | $14.83 USPS Ground Advantage, 3-4 business days | $16.47 FedEx Ground Economy, 1 business day | USPS |
| Philadelphia, PA 19102 | $15.05 USPS Ground Advantage, 4-5 business days | $16.47 FedEx Ground Economy, 2-3 business days | USPS |
| Atlanta, GA 30303 | $24.63 USPS Ground Advantage, 4-5 business days | $23.22 FedEx Ground Economy, 4-5 business days | FedEx |
| Chicago, IL 60601 | $24.63 USPS Ground Advantage, 7-8 business days | $26.59 FedEx Ground Economy, 3-4 business days | USPS |
| Dallas, TX 75201 | $29.62 USPS Ground Advantage, 4-5 business days | $26.71 FedEx Ground Economy, 4-5 business days | FedEx |
| Denver, CO 80202 | $33.87 USPS Ground Advantage, 5-6 business days | $32.61 FedEx Ground Economy, 5-6 business days | FedEx |
| Los Angeles, CA 90011 | $39.46 USPS Ground Advantage, 5-6 business days | $36.63 FedEx Ground Economy, 7-8 business days | FedEx |
| Seattle, WA 98101 | $39.46 USPS Ground Advantage, 7-8 business days | $36.63 FedEx Ground Economy, 8-9 business days | FedEx |
USPS won the 5 lb comparison on seven of the eight destinations, losing only the short hop to Philadelphia. By 20 lb FedEx had taken the lead on five of the eight — Atlanta, Dallas, Denver, Los Angeles and Seattle — while USPS still held Hoboken, Philadelphia and Chicago. That rules out a single crossover weight: the same 20 lb carton crosses over between Newark and Atlanta but does not cross over between Newark and Chicago, a lane of similar length. Philadelphia is the outlier in the set — the lead changes hands twice inside this range, to FedEx at 5 lb and back to USPS at 20 lb.
The two ends of the grid, 1 lb and 50 lb, do not offer a crossover to read at all — one carrier simply was not in the running.
| Destination | 1 lb — USPS | 50 lb — FedEx |
|---|---|---|
| Hoboken, NJ 07030 | $8.93 USPS Ground Advantage, 3-4 business days | $35.51 FedEx Ground Economy, 1 business day |
| Philadelphia, PA 19102 | $9.01 USPS Ground Advantage, 4-5 business days | $35.51 FedEx Ground Economy, 2-3 business days |
| Atlanta, GA 30303 | $9.91 USPS Ground Advantage, 4-5 business days | $58.19 FedEx Ground Economy, 4-5 business days |
| Chicago, IL 60601 | $9.91 USPS Ground Advantage, 7-8 business days | $62.08 FedEx Ground Economy, 3-4 business days |
| Dallas, TX 75201 | $10.09 USPS Ground Advantage, 4-5 business days | $70.77 FedEx Ground Economy, 4-5 business days |
| Denver, CO 80202 | $10.29 USPS Ground Advantage, 5-6 business days | $83.88 FedEx Ground Economy, 5-6 business days |
| Los Angeles, CA 90011 | $11.12 USPS Ground Advantage, 5-6 business days | $92.81 FedEx Ground Economy, 7-8 business days |
| Seattle, WA 98101 | $11.12 USPS Ground Advantage, 7-8 business days | $92.81 FedEx Ground Economy, 8-9 business days |
At 1 lb none of the eight destinations returned a FedEx rate among the five cheapest options — USPS Ground Advantage won by default, from $8.93 into Hoboken to $11.12 into Los Angeles and Seattle. At 50 lb the reverse happened: USPS did not return a rate on any of the eight lanes, and FedEx Ground Economy was the cheaper of the two networks compared here on every lane, from $35.51 into Hoboken and Philadelphia to $92.81 into Los Angeles and Seattle. It was not the cheapest rate returned: UPS Ground, which this page leaves out of the comparison, came in under it on all eight of those lanes. Below 70 lbs USPS is priced but sometimes simply not competitive enough to make a five-rate shortlist; above it USPS is not an option at all, a limit covered further down this page.
The cheaper column is the slower column
Every FedEx price that beat a postal price in these captures came from FedEx Ground Economy, the slowest tier FedEx sells for household parcels. Reading the two price columns without the two window columns gets the decision wrong.
What the quotes said
USPS Ground Advantage came back at 2-3 business days into Ohio and 4-5 into Arizona, at every weight it quoted. FedEx Ground Economy came back at 5-6 business days into Ohio and 9-10 into Arizona. Same box, same day, four extra business days on the western run.
What the carriers publish
USPS lists Ground Advantage at 2 to 5 days and Priority Mail at 2 to 3 days (usps.com, read 2026-07-29). FedEx states that delivery within the contiguous U.S. takes 1 to 5 business days on its ground services (fedex.com, read 2026-07-29). Both quoted windows sat at the slow end of the published ranges.
Which day of the week
FedEx publishes that FedEx Ground delivers to businesses Monday through Friday, while FedEx Home Delivery reaches residences every day of the week and carries a four-dollar residential surcharge per package. A Saturday arrival is normal for one and not offered by the other.
If the recipient is waiting on a birthday, an auction deadline or a return window, the postal row on these lanes bought three to five business days for a few dollars. If nobody is watching tracking, the economy tier is the cheaper way to move a heavy box and the wait costs nothing.
What each network will physically accept
Price stops mattering the moment a box falls outside a carrier's envelope. These are the ceilings each carrier publishes for United States packages, read on 2026-07-29.
| Limit | USPS | FedEx |
|---|---|---|
| Heaviest package | 70 lbs, stated as the maximum for a USPS package | 150 lbs on the ground services |
| Longest side | not published as a separate figure; the size test is length plus girth | 108 in |
| Length plus girth | 130 in, or under 108 in for Priority Mail and Priority Mail Express | 165 in, measured as length plus twice the width plus twice the height |
| Where it stops being a package | above 70 lbs there is no postal service to move it | heavier than 150 lbs, or a combined length and girth of more than 165 in, is handled as freight |
| Extra charge before the ceiling | additional fees may apply for dimensional weight or nonstandard size | an oversize charge applies past 96 in in length or 130 in in length or girth |
The gap between 70 and 150 lbs is the part worth remembering. Anything in that band is not a postal shipment at any price, which is why the 45 lb carton earlier still had a postal option on paper while a 90 lb one would not. Past 150 lbs, or past 165 inches of length and girth, FedEx itself stops calling the shipment a package, and the box belongs on a pallet.
Choosing between them without a spreadsheet
Light and small favors the mail
Under about 10 lb the postal network was cheaper on both lanes tested and quicker on both. Small dense parcels are what that network was built around, and nothing in this capture argued otherwise.
Heavy or bulky favors FedEx
Above 20 lb the FedEx economy tier led on both lanes, and past 70 lbs FedEx is the only one of the two still in the running. Volume rather than mass is often what pushes a box across that line.
Long lanes move the line
The crossover weight fell by a step when the destination changed from Ohio to Arizona. Quote the actual origin and destination rather than trusting a threshold somebody worked out on a different route.
Our calculator asks both carriers at once, along with UPS, and lists every rate that came back with its price and its window. Guest checkout, printable label, tracking attached. Shipping protection is offered during checkout where the carrier supports it for the route.
Common questions
Is FedEx or USPS cheaper?
It flips with weight. In the 2026-08-21 quotes on this page USPS was under FedEx at 1, 4 and 10 lb going to Ohio, and FedEx was under USPS at 20 and 45 lb. On the longer run to Arizona the flip happened between 4 and 10 lb instead.
Why did the cheaper FedEx price come with a longer delivery window?
Because the FedEx rows that undercut USPS were FedEx Ground Economy, the slowest tier. It quoted 5 to 6 business days into Ohio and 9 to 10 into Arizona, against 2 to 3 business days for USPS Ground Advantage into Ohio and 4 to 5 into Arizona.
How heavy can a package be with each carrier?
USPS states that the maximum weight for a USPS package is 70 lbs. FedEx states that packages up to 150 lbs. can be shipped on its ground services. Both figures were read from the carriers' own pages on 2026-07-29, and they mean anything between those two numbers is a FedEx question, not a postal one.
Does FedEx deliver on weekends?
FedEx publishes that FedEx Ground delivers to businesses Monday through Friday while FedEx Home Delivery delivers to residences every day of the week, and that a four-dollar residential surcharge is added per package on Home Delivery. Read from fedex.com on 2026-07-29.
Why did some requests come back without a FedEx price at all?
Each quote returns the five least expensive rates it found. On the 1 lb carton those five slots were taken by postal and UPS services, so no FedEx row appeared. That is a ranking outcome, not a refusal.
Does the FedEx-over-USPS crossover happen at the same weight on every route?
No. In an eight-destination grid out of Newark, NJ at 1, 5, 20 and 50 lb quoted 2026-08-23, USPS Ground Advantage undercut FedEx Ground Economy into Atlanta at 5 lb, $14.02 against $14.31, and FedEx took the lead by 20 lb, $23.22 against $24.63. On the Hoboken and Chicago lanes USPS was still cheaper at 20 lb. At 1 lb none of the eight destinations returned a FedEx rate at all, and at 50 lb none returned a USPS rate at all.
Where the carrier rules on this page come from
- United States Postal Service, Sending Packages — the 70 lbs weight ceiling, the 130 inch length plus girth test and the 108 inch limit on Priority Mail. Read 2026-07-29.
- United States Postal Service, Compare Mail Services — published delivery day ranges and tracking by service. Read 2026-07-29.
- FedEx, FedEx Ground and FedEx Home Delivery — the 150 lbs, 108 inch and 165 inch package limits, the contiguous US day range, the delivery days for each service and the residential surcharge. Read 2026-07-29.
- FedEx, Shipping large items — the oversize thresholds and the point at which a shipment is handled as freight. Read 2026-07-29.
Carriers refile prices and rewrite these pages without warning, and a single capture is a photograph rather than a rule. The tables above are what two networks answered for those exact cartons on 2026-08-21. Quote the box in your hands.