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Factorial Calculator
MATH CALCULATOR
Calculate n! exactly for whole numbers from 0 through 500, along with its digit count and trailing zeros.
Exact factorial3,628,800
Number of digits7
Trailing zeros2
Scientific estimate3.6288 × 10⁶
How it works
A factorial multiplies a whole number by every positive integer below it. Exact results use browser BigInt arithmetic rather than rounded floating-point numbers.
Formula
n! = n × (n − 1) × (n − 2) × … × 2 × 1, and 0! = 1.
Example
10! = 10 × 9 × 8 × … × 1 = 3,628,800. It contains seven digits and two trailing zeros.
Important limits
- The input is capped at 500 to keep exact results readable and responsive.
- The scientific form is an estimate; the expanded integer is exact.
- Factorial is defined here only for nonnegative whole numbers.
Frequently asked questions
Why does 0! equal 1?
This convention keeps counting formulas and the recursive identity n! = n(n−1)! consistent.
Why do factorials grow so quickly?
Each step multiplies the entire preceding result by another increasing integer.
Review notes
Exact values use integer multiplication; trailing zeros are counted from powers of five. Last reviewed September 30, 2026.