Factorial Calculator
Multiplies a number by every whole number below it.
n!
—
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Digits —
Trailing zeros —
log₁₀(n!) —
Reading this —
The formula
n! = n × (n − 1) × … × 2 × 1 0! = 1
Large values use ln n! = ln Γ(n + 1), which never overflows.
What to watch out for
Factorials grow faster than any fixed power. In ordinary double-precision arithmetic, 170! is the last one that fits, so a calculator that multiplies directly gives up at 171.
Frequently Asked Questions
What is 100 factorial?
About 9.3326×10^157, with 158 digits.
Why is 0! equal to 1?
There is exactly one way to arrange nothing. It also keeps formulas such as the one for combinations consistent.
How many ways can 10 items be ordered?
3,628,800.