A USPS shipping zone is a number from 1 to 9 that stands for how far a package travels. For USPS package services priced by zone, the zone and the package's weight set the postage, so the same box costs more to send across the country than across the state. You don't pick the zone: it comes from your ZIP Code and your customer's. That makes where you ship from one of the few zone levers you actually control.
What Are Shipping Zones?
Shipping zones are the distance bands carriers use to price a domestic package. USPS numbers its zones 1 through 9. Zone 1 is the shortest band, Zone 8 is everything beyond Zone 7, and Zone 9 is a separate band for three Pacific island nations whose mail USPS treats as domestic.
USPS does not measure the miles from your warehouse to the customer's door. Under Domestic Mail Manual (DMM) section 608.9.1, it measures from the centroid of the 3-digit ZIP Code area serving the origin Post Office to the centroid of the one serving the destination Post Office, using Labeling List L002, Column A. That is why two addresses about the same distance from you can land in different zones: the zone follows the centers of the two 3-digit areas, not the street addresses. Carriers set their rates partly on that zone.
What Are the USPS Shipping Zones?
USPS defines its zones in DMM section 608.9.4.2. The mile figures below are the DMM's approximate radii, measured between 3-digit ZIP Code area centroids, so read them as an estimate rather than a hard cutoff.
Here is the USPS zone chart as the DMM defines it:
- Zone 1: origin and destination in the same 3-digit ZIP Code area, or in two 3-digit areas whose centroids are up to 50 miles apart
- Zone 2: outside Zone 1, within about 150 miles
- Zone 3: outside Zone 2, within about 300 miles
- Zone 4: outside Zone 3, within about 600 miles
- Zone 5: outside Zone 4, within about 1,000 miles
- Zone 6: outside Zone 5, within about 1,400 miles
- Zone 7: outside Zone 6, within about 1,800 miles
- Zone 8: everything outside Zone 7
- Zone 9: the Republic of Palau, the Federated States of Micronesia, and the Republic of the Marshall Islands (the destinations listed in DMM 608.2.2)
Two details trip people up. Zone 1 is not a "local" rate; in the DMM, "Local" is a separate term for USPS Connect Local pieces. And a package mailed within the same 3-digit ZIP Code area takes the Zone 1 price whatever the distance between the two addresses, because the rule is about the 3-digit pair, not the miles.
For the exact zone between a specific pair of ZIP Codes, use the USPS Domestic Zone Chart. Enter your origin 3-digit ZIP prefix to see the full chart, or use the "Get Zone for ZIP Code Pair" tab, which USPS also directs you to for all inbound APO, FPO, and DPO mail. To see the zones across the contiguous US from one origin at a glance, or to look up the zone for any two ZIP Codes, use our USPS zone map.
How Zones Change What You Pay
On zoned services such as Priority Mail and USPS Ground Advantage, postage is set by weight and zone, so the same package generally costs more as the zone number rises. The gap also widens as the package gets heavier: in the USPS price list (Notice 123), the difference between a near zone and Zone 8 grows with each added pound. Zones matter most for brands that ship heavy products.
Priority Mail Flat Rate packaging is the exception. Its price doesn't change with the zone, so a heavy, dense item going to Zone 7 or 8 can cost less in a Flat Rate box than at the zoned price. Compare both for the order before you buy the label.
Box size can raise the price too. On Priority Mail and Ground Advantage, a box larger than 1 cubic foot (1,728 cubic inches) is charged on its actual weight or its dimensional weight, whichever is greater, and that billable weight is then priced by zone. USPS rounds each side up to the next whole inch before it measures, so a 12.1 x 12 x 11.8 inch box counts as 13 x 12 x 12 inches, or 1,872 cubic inches, and crosses the line. A light but bulky box going far pays on both counts. Our dimensional weight calculator shows the number before you ship.
The other half of the zone is where you ship from. If you pack orders at home, your ZIP Code sets the zone for every order, and the only way to change the mix is to ship from somewhere else, usually by moving inventory to a 3PL. Our zone map's breakdown of the USPS chart (effective October 1, 2026) shows how much origin matters: 2% of destination 3-digit ZIP areas are Zone 8 from Austin, compared with 17% from New York and 48% from Los Angeles, and 83% of areas from Austin fall in Zones 5 to 7.
Those are ZIP areas, not customers, though. A coastal warehouse sits close to the dense ZIP areas on its own coast, so a smaller Zone 8 share doesn't automatically mean a lower average zone for your orders. We look at that tradeoff in whether a central US 3PL beats a coastal one. Simpl ships every order from a single warehouse in Austin, which is why our zone map starts there.
A zone also isn't a delivery date. It's a pricing band; transit time depends on the service and the route.
Checking Your Own Zone Mix
Before you change boxes, services or warehouses, find out where your orders actually go.
- Export the ship-to ZIP Codes from your last few months of orders.
- Look up the zone for each one from your origin, on the USPS Domestic Zone Chart or our zone map, and count how many land in Zones 7 and 8.
- For heavier orders going far, price a Flat Rate box against the zoned rate.
- If you're comparing fulfillment partners, run the same ZIP Codes from each warehouse's ZIP Code and compare the zone mix your actual customers would get.