Factorial Calculator
Calculate factorial (n!) and double factorial (n!!). Useful for permutations, combinations, and mathematical calculations.
Inputs
Results
Factorial (n!)
120
Double Factorial (n!!)15
Factorial (n!)
120
How to Use This Calculator
- Start by filling in the input fields below. Results update instantly as you type, so you can experiment with different values to see how they affect the outcome.
- Number (n) — Enter a non-negative integer Minimum value: 0 (default: 5).
- Once all inputs are set, review your results in the Results panel. Here's what each output means:
- Factorial (n!) — shown as a numeric value. This is the primary result of this calculator.
- Double Factorial (n!!) — shown as a numeric value.
- Explore the related calculators below if you need deeper analysis or want to approach this topic from a different angle.
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Formula
n! = n × (n-1) × (n-2) × ... × 2 × 1Related Calculators
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