USPS Street Suffix Abbreviations (Publication 28)

A street suffix is the word at the end of a street name that says what kind of road it is — Street, Avenue, Boulevard, Court. USPS Publication 28, the Postal Addressing Standards, assigns each suffix a single standard abbreviation. STREET, Str and St all standardise to ST; COURT and the commonly typed CRT both standardise to CT.

USPS standardises these because mail is sorted by machine. A scanner reading an address matches it against the Address Management System database, and a non-standard suffix costs a match attempt. The same reasoning is why address forms, checkout validation and CASS-certified software return the standardised form no matter what a customer typed. The standard also asks for uppercase and no punctuation: 1200 MAIN ST STE 400, not 1200 Main St., Suite 400.

The abbreviations people look up most

Secondary unit designators (STE, APT, BLDG, FL)

A secondary unit designator identifies a unit inside a building rather than the street. STE stands for Suite, APT for Apartment, BLDG for Building, FL for Floor, RM for Room. Most take a number directly after them and belong on the same line as the street address — 1200 MAIN ST STE 400 — not on a separate line, which is the single most common formatting error in checkout forms.

Directional abbreviations

Directionals appear before the street name (a pre-directional, as in 224 E FOREST DR) or after it (a post-directional, as in 1600 PENNSYLVANIA AVE NW). They are always abbreviated.

Full street suffix list

134 suffix names, each with the variations that standardise to the same abbreviation. Publication 28 Appendix C1 runs to more than two hundred entries including rarely-seen variants; this covers the suffixes in ordinary use. Where an entry is listed here it matches the published standard, and anything absent should be checked against the official publication rather than assumed.

Frequently asked questions

What does STE stand for in an address?

Suite. It is a secondary unit designator and takes a number after it: STE 400.

What does CRT mean in an address?

It is a commonly written variation of Court. The USPS standard abbreviation is CT.

What is the abbreviation for Plaza in an address?

PLZ.

How do you abbreviate Trailer in an address?

TRLR, which is both a street suffix and a unit designator.

Does USPS require addresses to be abbreviated?

No, but it prefers it. Spelled-out addresses are delivered; standardised ones sort more reliably.

Related tools

• Random US address generator — produces addresses already written in this format.
• Address validator — standardises an address you paste in and shows what changed.
• USPS address formatting rules — the full standardisation rules in context.
• REST API documentation — the same formatting applied by the API.