Regex for us zip code
Match a US ZIP code in 5-digit or ZIP+4 (5-4) format.
The us zip code regex is ^\d{5}(-\d{4})?$ — copy it below, or open it in the explainer for a token-by-token breakdown.
The pattern
^\d{5}(-\d{4})?$Try it in the explainer → Download cheat sheet ↓
What it matches
123459021012345-6789
What it doesn't match
1234123456ABCDE12345-678
Token-by-token breakdown
Every part of the pattern, left to right:
| Token | Meaning |
|---|---|
^ | start of string (or line in multiline mode) |
\d{5} | exactly 5 times: digit (0–9) |
( | start of a capturing group |
- | literal text “-” |
\d{4} | exactly 4 times: digit (0–9) |
)? | end of group, optional (zero or one) |
$ | end of string (or line in multiline mode) |
Edge cases & gotchas
- Doesn't verify the ZIP code corresponds to a real US location
- Some ZIP codes start with 0 (e.g. 02134 in Massachusetts) — pattern handles this correctly
- Doesn't accept ZIP codes with spaces instead of hyphens (
12345 6789) - For Canadian postal codes (A1A 1A1) or UK postcodes, use entirely different patterns
Per-flavor variants
The pattern is identical across JavaScript, Python, and PCRE for this case. If you need to convert a flavor-specific pattern, use the flavor converter.
| JavaScript | ^\d{5}(-\d{4})?$ |
| Python | ^\d{5}(-\d{4})?$ |
| PCRE | ^\d{5}(-\d{4})?$ |
When NOT to use this regex
For address validation or normalization, use a postal-service API (USPS API, SmartyStreets, Lob). They verify the ZIP exists, attach a city/state, and confirm a deliverable address — which regex cannot do.
Standards & sources
This pattern is based on the following authoritative specification(s) and issuing authorities. Formats can change — always confirm against the primary source.
Related patterns
More patterns in the United States 🇺🇸 category: