Factorial Calculator
Find n factorial (n!), the product of every whole number from 1 to n, shown exactly.
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Factorial
- Digits
- Trailing zeros
- Scientific notation
- Exact value
- Work
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How to Calculate a Factorial
n factorial is the product of all whole numbers from 1 up to n. It counts the ways to arrange n different things in order.
n! = n × (n − 1) × … × 2 × 1 0! = 1
Trailing zeros = ⌊n/5⌋ + ⌊n/25⌋ + ⌊n/125⌋ + …
Worked Example
Tips
Factorials grow very fast: 10! is 3,628,800 and 70! is more than a googol (10¹⁰⁰). This page uses exact whole-number arithmetic, so every digit is correct. Factorials of negative numbers or decimals aren’t defined here (the gamma function extends them).