Calculate the factorial of any positive integer. A factorial (n!) is the product of all positive integers from 1 to n.
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Results
Factorial
120.00
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Formula
n! = n × (n-1) × (n-2) × ... × 2 × 1
How to Use This Calculator
How to Use
- 1
Enter a positive integer.
- 2
Click calculate to find its factorial.
Frequently Asked Questions
Frequently Asked Questions
What is 5! (five factorial)?
5! = 5 × 4 × 3 × 2 × 1 = 120
What is 0 factorial?
0! = 1 by definition. This is used in combinatorics and makes formulas work correctly.
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About This Calculator
This calculator uses the formula: n! = n × (n-1) × (n-2) × ... × 2 × 1. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
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