One shoebox-sized carton, six weights, two lanes, both services quoted in the same minute on 2026-07-29. UPS Ground was the cheaper of the pair every single time, from $10.31 at a pound to $24.33 at twelve pounds across the country. The interesting part is what the extra buys, and on one of these two lanes the answer was nothing.
A 12 by 9 by 6 in box leaving Berkeley Heights, NJ, weighed up in stages so the two price curves can be read against each other.
Rows appear here only where both services came back in the same request, so every line is a genuine either-or rather than two quotes stitched together. Prices are the totals checkout collects, not a base rate with surcharges to follow.
| Weight | USPS Priority Mail | UPS Ground | Estimate returned |
|---|---|---|---|
| 1 lb | $14.49 | $10.31 | 4-5 business days on both |
| 8 lb | $21.91 | $16.19 | 4-5 business days on both |
| 12 lb | $21.91 | $16.19 | 4-5 business days on both |
| 20 lb | $21.91 | $16.19 | 4-5 business days on both |
Read the bottom three rows across and both columns stop moving. Eight pounds, twelve pounds and twenty pounds all priced the same on each service, because this carton had already reached the band where the box governs the rate instead of the scale. If you are paying for that band anyway, filling the empty corners of the carton is the only part of this whole page that is genuinely free.
Down the columns, the premium ran a little over four dollars at one pound and a little under six at the heavier weights. Both services came back with the same arrival estimate on this lane, which makes that premium hard to justify on a three-state hop.
Distance is what separates these two services, so the second lane runs the same box to downtown Los Angeles. Here the estimates split, and the gap between the two prices moves in the opposite direction to the one most people expect.
| Weight | USPS Priority Mail | UPS Ground |
|---|---|---|
| 3 lb | $22.34 4-5 business days | $15.93 6-7 business days |
| 12 lb | $28.19 4-5 business days | $24.33 6-7 business days |
At three pounds the faster label costs six dollars and change for two days saved. At twelve pounds the same two days cost under four. Heavier freight narrows the gap because the ground price climbs with weight faster than the postal one does, so the honest rule from this capture is to buy the upgrade on the heavy long-haul box and skip it on the light one.
The Priority Mail page at usps.com/ship/priority-mail.htm, read 2026-07-29, gives the delivery time as 2-3 Days, a 70 pound maximum, and USPS Tracking with up to 100 dollars of coverage on most shipments, subject to restrictions and exclusions.
The UPS domestic services page, read 2026-07-29, gives Ground as one to five business days, with packages up to 150 lbs and 108 in long. Nothing on that page promises a fixed calendar date for a Ground parcel.
Neither published range is a commitment for your specific pair of ZIP codes. The window shown next to the price at checkout is calculated for the actual lane, and that is the number worth trusting.
Those two published ranges overlap heavily, which is exactly why a short lane shows no difference at all. Priority Mail separates itself over distance, where a ground network needs extra days to hand a parcel between terminals and the postal network does not slow down as much.
Neither of these two services was the cheapest thing on the screen. USPS Ground Advantage sat below both on the Chicago lane, at $9.91 for the one pound box and $13.29 at eight, twelve and twenty pounds, on the same 4-5 business day estimate the other two showed.
That matters for anyone shipping a few boxes a week rather than one parcel a year. Choosing between Priority Mail and UPS Ground on a short lane is a choice between the second and third cheapest options, and the arrival estimate stayed the same across all three. One more figure worth keeping: for the twenty pound carton, the postal counter price for Priority Mail came back as $46.95 against the $21.91 above, so the label you buy at home and the label you buy at a window are not remotely the same purchase.
Sources: USPS Priority Mail, usps.com/ship/priority-mail.htm, read 2026-07-29; UPS domestic shipping services, ups.com/us/en/support/shipping-support/shipping-services/domestic, read 2026-07-29. Carriers change both prices and standards without notice, so quote your own parcel before you commit.
Not in this capture. UPS Ground came in under Priority Mail at every weight we quoted on both lanes on 2026-07-29, by a little over four dollars on the one-pound box and by closer to six on the heavier ones.
It depends entirely on the distance. USPS publishes 2-3 Days for Priority Mail and UPS publishes one to five business days for Ground, and on our short lane the two estimates came back identical. Coast to coast the Priority Mail estimate was two business days earlier.
The price ranking did not change at all between 1 and 20 lb. What changed is the size of the gap, which was widest on the light coast-to-coast box and narrowest on the heavy one, so the speed upgrade is worth most on a heavy parcel crossing the country.
Underneath both of them on price. On the Chicago lane it returned $9.91 at one pound and $13.29 at eight, twelve and twenty pounds, which is the floor for this box on this route.
USPS states on its Priority Mail page that most shipments carry USPS Tracking and up to 100 dollars of coverage, with restrictions and exclusions applying. The same page gives 70 pounds as the maximum weight.