This chart strips out every other carrier and shows what the Postal Service alone quoted for a ladder of weights on 2026-07-27, then adds the fixed list prices USPS publishes for containers where the scale never matters. One network, examined properly.
Band pricing produces dips and jumps no smooth chart would predict. We kept every one of them.
Each weight used a box sized the way that weight actually packs, from roughly 10 by 8 by 4 inches at the bottom rung to 18 by 14 by 12 at the top shown here. A dash means the service was missing from the five options the calculator returned for that request.
| Weight | Ground Advantage | Priority Mail |
|---|---|---|
| 1 lb | $9.91 | $14.49 |
| 2 lb | $8.48 | – |
| 3 lb | $8.48 | – |
| 5 lb | $14.67 | – |
| 10 lb | $20.86 | – |
| 15 lb | $23.69 | – |
| 20 lb | – | – |
| Weight | Ground Advantage | Priority Mail |
|---|---|---|
| 1 lb | $11.12 | $16.47 |
| 2 lb | $11.04 | $22.34 |
| 3 lb | $11.04 | $22.34 |
| 5 lb | $20.84 | $32.26 |
| 10 lb | $30.09 | – |
| 15 lb | $35.33 | – |
| 20 lb | $55.71 | – |
| Product | List price |
|---|---|
| Priority Mail flat-rate envelope | $12.90 |
| Priority Mail small flat-rate box | $13.65 |
| Priority Mail medium flat-rate box | $24.80 |
| Priority Mail large flat-rate box | $34.00 |
| Priority Mail Express flat-rate envelope | $35.90 |
| Media Mail, 1 lb | $4.39 |
| Media Mail, 10 lb | $11.02 |
The flat-rate rows are the escape hatch from everything above them: pack the container, pay the sticker, ignore the zone map. Media Mail is the outlier bargain of the whole postal catalog, but it exists for qualifying media shipments and USPS decides what qualifies, so read the rules before betting on it.
The eastern table's opening rungs prove the point: adding a pound to a 1 lb box would have saved money on capture day. Before you trim two ounces of packing to duck under a whole number, check which side of a band you're on; sometimes the heavier side is the cheap one.
From 15 to 20 lb the coast-to-coast Ground Advantage quote leapt from $35.33 to $55.71, and after that USPS left the results entirely. If your box is flirting with that territory, splitting the load or switching networks is the move worth pricing.
USPS in isolation answers one question. Our all-carrier weight table shows the same ladder with UPS and FedEx competing, and the three-way comparison condenses it into a verdict per checkpoint weight. Same day of data, three ways to slice it.
Not linearly. Rates move in weight bands, and our 2026-07-27 quotes caught the bands misbehaving in your favor: a 2 lb box out of Newark cost $8.48 while the 1 lb one cost $9.91. The chart is a staircase with uneven steps, not a slope.
In our capture the Postal Service faded out of contention. Its last eastern appearance was $23.69 at 15 lb, its last western one $55.71 at 20 lb, and beyond those weights UPS and FedEx ground tiers filled every returned slot. Heavy boxes are simply not where USPS competes hardest.
Sometimes, and the trigger is density plus distance. Notice 123 lists the medium flat-rate box at $24.80 retail; our quoted 10 lb western Ground Advantage rate was $30.09. A heavy, compact item crossing the country in that box comes out ahead. A light or local one usually doesn't.
Yes, deliberately. It isolates one carrier so the internal logic of its pricing is visible. When you want USPS lined up against UPS and FedEx at the same weights, our all-carrier weight table and the three-way comparison both do exactly that.