Every price here came from one 2026-07-24 run against the exact cartons and ZIP pairs in the tables. Quote your own before you buy.
Cheapest at each weight
| Box and weight | Cheapest | Next cheapest | Gap |
|---|---|---|---|
| 9 × 6 × 4 in, 1 lb | $10.75 UPS Ground Saver | $11.05 USPS Ground Advantage | $0.30 |
| 12 × 9 × 6 in, 5 lb | $8.94 USPS Ground Advantage | $13.35 UPS Ground Saver | $4.41 |
| 16 × 12 × 10 in, 10 lb | $17.56 UPS Ground Saver | $20.86 USPS Ground Advantage | $3.30 |
| 18 × 14 × 12 in, 20 lb | $23.00 UPS Ground Saver | $26.52 FedEx Ground Economy | $3.52 |
| 24 × 18 × 18 in, 50 lb | $45.01 UPS Ground | $58.93 FedEx Ground Economy | $13.92 |
Coast to coast
| Box and weight | Cheapest | Next cheapest | Gap |
|---|---|---|---|
| 9 × 6 × 4 in, 1 lb | $11.75 UPS Ground Saver | $12.33 UPS Ground | $0.58 |
| 12 × 9 × 6 in, 5 lb | $14.16 USPS Ground Advantage | $16.88 UPS Ground Saver | $2.72 |
| 16 × 12 × 10 in, 10 lb | $24.69 FedEx Ground Economy | $25.51 UPS Ground Saver | $0.82 |
| 18 × 14 × 12 in, 20 lb | $35.03 FedEx Ground Economy | $35.06 UPS Ground Saver | $0.03 |
| 24 × 18 × 18 in, 50 lb | $76.04 UPS Ground | $88.09 FedEx Ground Economy | $12.05 |
Who actually wins
Across the ten quotes above: UPS won 6 of 10, USPS won 2 of 10, FedEx won 2 of 10. No carrier is cheapest everywhere, and the gap between first and second place is often small enough that delivery speed decides it instead of price.
Small and light
USPS Ground Advantage took most of the small boxes and stayed within a couple of dollars of the field on the rest. It is the default worth beating.
Heavy and bulky
Above roughly 20 lb, UPS Ground pulled ahead — at 50 lb it was the only carrier under $50 on the Chicago lane.
Slow-lane services
UPS Ground Saver and FedEx Ground Economy undercut standard ground on several boxes, at the cost of a day or two and a final-mile handoff to USPS.
Common questions
What is the cheapest way to ship a package?
It depends on the box, not on the carrier. In the run on this page USPS Ground Advantage was cheapest on the light boxes and UPS Ground on the heavy ones, with the ordering flipping again coast to coast. Comparing all three for the exact box is the only way to know.
Is USPS always cheaper than UPS and FedEx?
No. USPS led the small boxes here, but at 50 lb it returned no rate at all on one carton while UPS Ground quoted $45.01. Above about 20 lb the ground networks are usually the better buy.
Does a bigger box cost more even if the weight is the same?
Usually yes. Two figures compete for the bill and the larger one takes it: what the scale reads, and what you get if you multiply the three sides in inches and divide by 139. Tightening the carton is the cheapest change most shippers can make.
Are flat rate boxes cheaper?
Only when your item is dense and travels far. For a light item, or a short zone, weight-based and cubic pricing usually beat a flat rate. The calculator prices the actual box so you can see which side you are on.
Do these prices include tracking?
Yes. Every service quoted here is tracked end to end, and the tracking number reaches you by email as soon as the label is bought.