USPS, UPS and FedEx divide the US into shipping zones (1 - 8) based on the distance between origin and destination ZIP codes. The further the package travels, the higher the zone number and the more expensive the shipping cost.
Zone
Distance (miles)
Example Route
1
0 - 50
Local / same city
2
51 - 150
Los Angeles โ San Diego
3
151 - 300
Los Angeles โ Phoenix
4
301 - 600
Los Angeles โ Denver
5
601 - 1,000
Los Angeles โ Chicago
6
1,001 - 1,400
Los Angeles โ Dallas
7
1,401 - 1,800
Los Angeles โ New York
8
1,801+
Los Angeles โ Boston
USPS Flat Rate Box Prices (2025)
Flat Rate boxes ship any weight (up to 70 lbs) to any zone in the US at one fixed price. Best for heavy items going long distances.
Box Type
Dimensions
Ground / Retail
2-Dayยฎ
Priority Mail Express
Small Flat Rate Box
8โ " ร 5โ " ร 1ยพ"
$10.40
$10.40
โ
Medium Flat Rate Box (Top-Load)
11ยผ" ร 8ยพ" ร 6"
$17.60
$17.60
โ
Medium Flat Rate Box (Side-Load)
13โ " ร 11โ " ร 3โ "
$17.60
$17.60
โ
Large Flat Rate Box
12ยผ" ร 12ยผ" ร 6"
$24.40
$24.40
โ
Priority Mail Express Flat Rate Box
12ยฝ" ร 9ยฝ" ร 2"
โ
โ
$30.95
Priority Mail Express Flat Rate Box (Big)
15โ " ร 14โ " ร 3"
โ
โ
$46.95
Pro Tip
If your package weighs more than 10 lbs and is traveling Zone 5+, a Flat Rate box is almost always cheaper than regular Priority Mail by weight.
USPS Regional Rate Boxes
Regional Rate boxes are priced by zone:
Box Type
Max Weight
Zone 1 - 2
Zone 3
Zone 4
Regional Rate Box A
15 lbs
$9.75
$12.50
$15.25
Regional Rate Box B
20 lbs
$12.50
$16.50
$20.75
How to Save on Shipping
๐ Use Flat Rate Boxes for Heavy Items
If your package weighs over 10 lbs, check USPS Flat Rate pricing. A 50-lb package costs the same as a 1-lb package in a Flat Rate box. Especially valuable for Zone 7 - 8 shipments.
โ Keep It Under Key Weight Thresholds
Shipping costs jump at certain weights. Keep packages under 1 lb, 2 lbs, 5 lbs, 10 lbs, 20 lbs, and 50 lbs to avoid crossing into the next price tier. Use a lighter box or poly mailer.
๐ Dimension Weight (DIM) Matters
All three carriers use dimensional weight (DIM) pricing. If your box is large but light, you pay for the space it takes up. DIM divisor for USPS/UPS/FedEx is typically 139 (domestic). Formula: (L ร W ร H) รท 139. Round up to next pound. Keep boxes as small as possible.
๐ท Use Your Own Packaging
For lighter items, using your own packaging with USPS Priority Mail Cubic (for packages under 0.5 cu ft) can be cheaper than Flat Rate boxes. UPS and FedEx also offer discounts for online labels.
Compare Carriers Every Time
No single carrier is cheapest for every package. Use this calculator to compare all three before printing a label. Sign up for free business accounts to get up to 89% off retail rates.
๐ Ship Ground When Possible
Ground shipping is significantly cheaper than 2-Day or Overnight. Unless the package is urgent, always pick Ground to save 40 - 70%.
โ Avoid Retail Counter Rates
:
๐ Zone Skipping for Frequent Shippers
If you ship many packages to the same region, consolidate and use a zone-skipping service (UPS SurePost, FedEx SmartPost) to hand off to USPS for final delivery at a lower cost.