ZIP Code Validator
Validate US ZIP codes — check one or many at once for correct 5-digit or ZIP+4 format.
Input
Output
| ZIP Code | Status | Format |
|---|---|---|
| No data yet | ||
Guides
What does this tool check?
It validates that each entry matches a real US ZIP code format: either the standard 5-digit ZIP code (90210) or the extended ZIP+4 format (90210-1234), which adds a four-digit code identifying a more specific delivery area.
How this tool works
Paste one ZIP code per line — the tool checks each one independently and reports whether it's valid, and which format it matched. The summary line gives you a quick valid/invalid count across the whole batch.
What counts as valid
- 5-digit: exactly five digits, nothing else (
10001). - ZIP+4: five digits, a hyphen, then exactly four digits (
99501-3456).
Anything else — too few or too many digits, a missing or misplaced hyphen, letters, or extra characters — is flagged invalid. This is a format check only: it confirms the ZIP code is shaped correctly, not that it corresponds to a real, currently-assigned postal area.
Common uses
- Validating a batch of ZIP codes before importing them into a database or mailing list
- Checking user-submitted address forms for correctly formatted ZIP codes
- Spotting malformed entries in a CSV export before sending mail
- Quickly distinguishing 5-digit from ZIP+4 entries in mixed data
Privacy
This tool runs entirely in your browser. Your data is never uploaded to a server.
Use it from code
From 3 credits per callREST API
curl -X POST https://api.iotools.cloud/v1/tool/zip-code-validator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"zipCodes": "90210\n10001\n99501-3456\n12345\n00000\n123\n90210-\n90…"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `zip-code-validator` tool (ZIP Code Validator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.