JavaScript RegExp {n} Exact Quantifier

What Is the {n} Quantifier?

Place {n} after a token to match it exactly n times — no fewer, no more for that run. Ideal for fixed-width fields like \d{4} (year) or \d{5} (ZIP shape).

token{n}     → exactly n of token
\d{3}        → "123" ✓ · "12" ✗ · "1234" still finds "123"
(ab){2}      → "abab" ✓

{3} exact    ·  {3,} three or more  ·  {2,4} between 2 and 4
^\d{5}$      → whole string is exactly five digits

How to Use {n}

Attach {n} to the token whose length must be fixed.

1. Choose the token (character, class, or group) — e.g. \d, a, (ha).
2. Add {n} with the exact count — e.g. \d{3}, (ha){2}.
3. Add surrounding literals or separators when building dates, IDs, or codes.
4. Use ^ and $ when the entire string must be that exact length.

Pseudocode

pattern = <token>{n}

count = 0
while count < n:
    if next input matches <token>:
        count = count + 1
    else:
        fail

// exactly n succeeded — do not require a (n+1)th match
continue with rest of pattern

Cheat Sheet

Keep these facts handy while writing fixed-count patterns.

Live Preview

Pick an exact-count pattern and a sample string to see test() / match() results.

pattern = /\d{3}/
text    = "12"
test()  → false
match() → null

/* need exactly three digits */

JavaScript Examples

Short, copy-ready snippets. Open DevTools Console, or use Try It Yourself for a live editor.

const samples = ["12", "123", "1234", "abc123def"];

samples.forEach((s) => {
  console.log(s, s.match(/\d{3}/));
});

12 null
123 ["123"]
1234 ["123"]
abc123def ["123"]

const words = ["hahaha", "haha", "hahahaha"];

words.forEach((w) => {
  console.log(w, /(ha){3}/.test(w));
});

hahaha true
haha false
hahahaha true

const rule = /^\d{5}$/;

console.log(rule.test("90210"));   // true
console.log(rule.test("9021"));    // false — too short
console.log(rule.test("902101"));  // false — too long
console.log(rule.test("9021a"));   // false — not all digits

true
false
false
false

Performance Notes

Exact counts on simple tokens are fast and predictable. Prefer \d{n} over open .{n} when you know the character class, and anchor when validating whole fields.

Key Takeaways