Factorial Calculator

Enter a non-negative integer to calculate n! and view digit count, notation details, and quick reference information.

Enter a non-negative integer only. This calculator currently supports values up to 500.

Result will appear here.
Metric Value

Privacy: calculations run locally in your browser. No inputs are stored or transmitted.

How it works

Factorial is defined as:
n! = n × (n−1) × (n−2) × ... × 2 × 1

Special case:
0! = 1

This calculator uses exact integer arithmetic with JavaScript BigInt, so the factorial value is not approximated.

Examples

  • 0! = 1
  • 5! = 120
  • 10! = 3,628,800
  • 20! is already a very large integer

FAQ

  • What is a factorial?

    The factorial of n is the product of all positive integers from 1 to n. Example: 5! = 120.

  • What values can factorial use?

    Factorials are defined for non-negative integers only.

  • Why do factorials grow quickly?

    Each step multiplies by a larger integer, so factorial values increase very rapidly.

  • Why does this calculator limit very large inputs?

    Factorials become extremely large very quickly. The limit keeps the page responsive and readable.

  • Are my inputs stored?

    No. All calculations run locally in your browser.

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