★ India · regex

Regex for Indian PIN Code

India Post PIN codes are six digits. The first digit is a postal region (1–8, and 9 for the Army Postal Service), so it can't be 0. Some people write them with a space after the third digit.

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Try the indian pin code pattern

Read it in plain English (best-effort)

^start of a line
[1-9]one character from: 1–9
[0-9]one character from: 0–9
{2}exactly 2 of the previous
the character ' '
?the previous is optional
[0-9]one character from: 0–9
{3}exactly 3 of the previous
$end of a line

Test text

One sample per line works well with the m flag on anchored patterns.

Waiting for a pattern

The pattern, piece by piece

/^[1-9][0-9]{2} ?[0-9]{3}$/

Pattern explanation
Part	What it does
`^[1-9]`	postal region: 1–9, never 0
`[0-9]{2}`	sub-region and sorting district
`?`	optional space after three digits
`[0-9]{3}$`	the delivery post office

What it accepts and rejects

Every sample below is checked automatically in JavaScript and Python. The tester above is preloaded with all of them, one per line.

Should match
Should match
`110001`	✓
`560001`	✓
`400 001`	✓
`700019`	✓
`682001`	✓
`302001`	✓

Should not match
Should not match
`011000`	✗
`11000`	✗
`1100011`	✗
`11 0001`	✗
`ABCDEF`	✗
`110-001`	✗

Copy it into your code

RE2-safeNo lookarounds or backreferences, so the same pattern works in Go's RE2 engine and in Rust's regex crate.

Language

const indianPincodeRe = /^[1-9][0-9]{2} ?[0-9]{3}$/;

export function isValidIndianPincode(value) {
  return indianPincodeRe.test(value.trim());
}

When not to use regex for this

To check a PIN code exists and fetch its city and state, use India Post's directory data rather than a pattern.

Questions engineers actually ask

Can a PIN code start with 0?

No. The first digit identifies one of the postal regions, which are numbered from 1.

Should I store the space?

No. Strip it and store the six digits.

What is catastrophic backtracking?

Some patterns, usually nested quantifiers like (a+)+, make a backtracking engine try an exponential number of paths on input that almost matches. The tester stops any run after 300ms, so a bad pattern can't freeze your tab. In production, that same pattern can take down a server (a ReDoS attack).