Math
Factorial Calculator
Calculate the factorial of any integer from 0 to 1000. Get the result, scientific notation, and digit count.
10!
3.628800e+6
Number of Digits
7
Full result
3628800
Frequently asked questions
What is a factorial?
A factorial (n!) is the product of all positive integers from 1 to n. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120. By definition, 0! = 1.
Why can't you show the full number for n > 170?
170! has 309 digits. 1000! has 2,568 digits. We show the exact value up to 170! and use scientific notation beyond that.
Where are factorials used?
Factorials are fundamental in combinatorics (permutations and combinations), probability theory, calculus (Taylor series), and many areas of mathematics.
What's the largest factorial I can calculate?
You can input any number from 0 to 1000. Results up to 170! are shown exactly; larger values use Stirling's approximation in scientific notation.
Calculate the factorial of any integer from 0 to 1000. See the complete result for smaller numbers, or scientific notation and digit count for larger ones.