US addresses look simple, but USPS routes on standardized abbreviations and the ZIP code, and non-standard street or unit text is the usual cause of returns. Here is the correct format, a real example, and the mistakes that trigger failed deliveries.
A US label is recipient, the street address with any unit, then the city, two-letter state, and ZIP on one line, then the country.
Jane Smith personal or business recipient350 Fifth Avenue, Suite 6800 use standardized suffixes (<code>Ave</code>, <code>St</code>) and unit designators (<code>Suite</code>, <code>Apt</code>)New York spelled out in fullNY the two-letter USPS state abbreviation10118 5 digits or ZIP+4, after the state on the same lineUNITED STATES required for inbound international shipmentsThe ZIP code drives USPS routing, and in ZIP+4 form it narrows delivery to a block or building. It sits after the two-letter state on the city line.
The country-specific rules that generic autocomplete and single-line address fields tend to get wrong.
USPS expects the two-letter state abbreviation, for example NY, CA, TX. Spelling the state out or using the wrong code slows automated sorting.
USPS standardizes suffixes (Street to ST, Avenue to AVE) and directionals (North to N). A validated label normalizes these so the barcode scans cleanly.
Secondary units use designators like APT, STE, or UNIT with the number. A missing apartment number is one of the top causes of undeliverable-as-addressed mail.
USPS delivers to PO boxes; UPS and FedEx do not. Shipping a courier order to a PO box guarantees a failed delivery, so the address type should be checked against the carrier.
Each of these passes a basic "is this field filled in" check but fails at the carrier, turning into a redelivery, a return, or an address correction fee.
10018 vs 10118) points to a different area and triggers a correction.New York instead of NY, or the wrong two-letter code, slows sorting.Avenue or Steet fails address matching against USPS data.How the major carriers handle United States addresses, and what your label needs to satisfy each one.
The universal carrier and the only one that delivers to PO boxes. Its CASS-certified matching keys off a clean street address plus ZIP, so validate both before printing the label.
The dominant private carriers for parcels. They require a physical street address (no PO boxes) and charge address correction fees on mismatched or incomplete addresses.
Handles inbound international shipments to the US. Include the country line and a valid ZIP+4 where possible to avoid customs and routing delays.
Address Guard checks United States addresses against carrier and postal databases before the order ships, normalizes the format, and flags the errors that cause failed deliveries. 240+ countries, $0.05 per check.
Part of the Address Guard international address format guide, covering 240+ countries.