Calculate the factorial of a number

Multiply the integers from 1 to n recursively.

JavaScript Version 1.0.0 · MIT · .md

function factorial(n) { return n <= 1 ? 1 : n * factorial(n - 1); }

Input & expected output

5

120

The edge case

0

1

Know the limits

• The lab stops at 18: 19! exceeds Number.MAX_SAFE_INTEGER. Use BigInt for larger values.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Clamp a number to a range — Keep a number inside an inclusive minimum and maximum.
• Round to a number of digits — Apply decimal scaling and JavaScript rounding for display-oriented values.
• Add an ordinal suffix to a number — Append st, nd, rd or th to a positive integer.