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Kenya Postal Code validator
How the postal code format works
- Format
- 5 digits
- Example
- 00100
Things to watch for
- Format-only check — does not confirm the postal code actually exists
- Always exactly 5 digits with no separators, including any leading zero (Nairobi's GPO is 00100, not 100)
- Posta Kenya's system, set up in 1977, routes to a post office box rather than a street address — Kenya has never had door-to-door residential delivery at scale
^[0-9]{5}$A Kenyan postal code is the 5-digit code Posta Kenya uses to route mail to a post office box — for example 00100 for Nairobi’s General Post Office. Because Kenya’s postal system was built in 1977 around PO Box delivery rather than door-to-door street addressing, the code identifies a distribution center and delivery office rather than a specific building, and Nairobi’s central postal region keeps its leading zero as a real, required part of the code rather than a formatting nicety. Anyone validating a Kenyan shipping address, checkout form, or spreadsheet of customer records needs the leading zero preserved and the full 5 digits present before it’s trusted.
A common data-entry slip is dropping Nairobi’s leading zero when a form or spreadsheet treats the postal code as a number rather than text, silently shortening 00100 to 100 — a length check catches this immediately.
How this validator works
This tool checks that the input is exactly 5 digits, leading zeros included, with no letters, spaces, or hyphens, entirely in your browser — nothing is sent to a server, and there’s no signup.
What a pass doesn’t tell you
A Kenyan postal code carries no check digit, so confirming it’s 5 digits long is the most a client-side tool can do — not that Posta Kenya has assigned it to a real post office. Confirming that requires Posta Kenya’s own postal code lookup.
Scope: this page and tool cover postal code format validation only — not address or PO Box lookup, or confirming a code is currently in use.
postal code FAQ
Why does Nairobi's postal code start with a zero?
Because Posta Kenya's 5-digit system, set up in 1977, groups Nairobi's postal region under 00 — so the General Post Office's code is 00100, not 100. Dropping the leading zero produces a code that's the wrong length and won't match a real Kenyan postal code.
Does a Kenyan postal code route to a street address?
Not typically. Kenya has never built out door-to-door residential mail delivery at national scale — a postal code identifies a post office box location, so mail addressed with a postal code is routed to that PO Box rather than a specific street.
Does a correctly formatted postal code mean it actually exists?
No. This tool only confirms the string is 5 digits — it doesn't check it against Posta Kenya's actual assignment list. Confirming a code is real requires Posta Kenya's own postal code lookup.