Math Calculators

Factorial Calculator

Use this free factorial calculator to calculate accurate results instantly with clear inputs, formulas, and rounded answers.

Free browser-based tool • No signup required
Factorial

Factorial Calculator

Factorial
Digits in result
Results are estimates for informational purposes. Verify critical calculations and project requirements independently.

Calculator Inputs and Outputs

Inputs

  • Whole number — example: 8

Results

  • Factorial
  • Digits in result

Formula used

n! = n × (n − 1) × … × 1, with 0! = 1.

How to Use the Factorial Calculator

Enter the requested values, review the units, and select Calculate Factorial. The result updates immediately using the formula below.

Formula

n! = n × (n − 1) × … × 1, with 0! = 1.

Example and Accuracy

The default values provide a working example. Change any input to calculate your own result. The calculator keeps full internal precision and rounds displayed values for readability.

Important Note

This calculator provides an informational estimate. Verify critical financial, medical, construction, scientific, or legal decisions with an appropriate qualified professional.

Calculation Standards

This tool uses documented formulas and high-precision internal values. Displayed results may be rounded for readability. Review the assumptions and verify important decisions with a qualified professional.

Read our calculation methodology