We quoted the same packed boxes at ten weights on two real lanes and let the carriers argue in dollars. The short version: USPS owns everything under 5 lb, then hands the ladder to UPS and never takes it back.
Each row pits the best USPS quote against the best UPS quote for one identical package, captured live on 2026-07-27.
Ten boxes, sized the way people actually pack them, from a 1 lb parcel around 10 by 8 by 4 inches up to a 50 lb carton around 24 by 18 by 14. Every figure below is the cheapest quote each carrier returned for that box through the SMKlog calculator, and it's the exact amount checkout would have collected.
| Weight | Best USPS | Best UPS | Cheaper carrier |
|---|---|---|---|
| 1 lb | $9.91 Ground Advantage | $10.31 Ground | USPS |
| 2 lb | $8.48 Ground Advantage | $10.52 Ground Saver | USPS |
| 3 lb | $8.48 Ground Advantage | $12.07 Ground Saver | USPS |
| 5 lb | $14.67 Ground Advantage | $13.65 Ground Saver | UPS |
| 10 lb | $20.86 Ground Advantage | $17.56 Ground Saver | UPS |
| 15 lb | $23.69 Ground Advantage | $20.50 Ground Saver | UPS |
| 20 lb | no USPS quote | $23.00 Ground Saver | UPS |
| 30 lb | no USPS quote | $31.52 Ground | UPS |
| 40 lb | no USPS quote | $38.45 Ground | UPS |
| 50 lb | no USPS quote | $45.01 Ground | UPS |
| Weight | Best USPS | Best UPS | Cheaper carrier |
|---|---|---|---|
| 1 lb | $11.12 Ground Advantage | $12.99 Ground | USPS |
| 2 lb | $11.04 Ground Advantage | $13.29 Ground Saver | USPS |
| 3 lb | $11.04 Ground Advantage | $15.53 Ground Saver | USPS |
| 5 lb | $20.84 Ground Advantage | $19.25 Ground Saver | UPS |
| 10 lb | $30.09 Ground Advantage | $25.51 Ground Saver | UPS |
| 15 lb | $35.33 Ground Advantage | $30.48 Ground Saver | UPS |
| 20 lb | $55.71 Ground Advantage | $35.06 Ground Saver | UPS |
| 30 lb | no USPS quote | $51.92 Ground | UPS |
| 40 lb | no USPS quote | $65.52 Ground | UPS |
| 50 lb | no USPS quote | $76.04 Ground | UPS |
Where a cell reads "no USPS quote", the Postal Service simply didn't surface in the top rates the calculator returned for that box on quote day. The 20 lb cross-country row shows why: Ground Advantage came back at $55.71 against $35.06 for UPS Ground Saver, a gap of over twenty dollars on one package. Carriers refile rates constantly, so treat the table as a snapshot and run your lane fresh before deciding.
The Postal Service already drives past every address in America, so a small parcel costs it very little to absorb. That structural edge shows up as the $8.48 two-pounder in the Newark table, a price UPS never approached at that weight.
UPS pricing climbs gently as pounds pile on, while Ground Advantage jumps hard between the 3 and 5 lb rungs on both lanes. Ground Saver, the economy tier that trades a day or two for money, is what actually flips the ladder.
Newark to Atlanta on UPS Ground quoted 3-4 business days at $10.31, forty cents above the 6-7 day USPS row. Some swaps buy speed nearly for free, and you only spot them with both carriers priced side by side.
In our 2026-07-27 quotes, USPS Ground Advantage held the low rung from 1 to 3 lb on both test lanes, bottoming at $8.48 for a 2 lb box from Newark to Atlanta. From 5 lb upward a UPS economy tier undercut it every time, and past 20 lb USPS stopped appearing in the quotes at all.
The crossover in this data sits at 5 lb. Newark to Atlanta went $13.65 UPS Ground Saver against $14.67 USPS Ground Advantage, and Los Angeles to New York went $19.25 against $20.84 for the same pairing. Below that rung USPS won; above it the gap kept widening in UPS's favor.
Often, on ground tiers. On the Newark to Atlanta quotes, UPS Ground carried a 3-4 business day window while USPS Ground Advantage carried 6-7. Cross-country the two evened out, with both carriers quoting 6-7 business days on their cheapest tiers.
Yes. Every dollar figure on this page is the full checkout amount the SMKlog calculator returned on 2026-07-27, with SMKlog's own charge folded in. Nothing gets added after you pick a rate.