How to use the factorial calculator
Compute n! and related counts. Enter number n in the field above; the n!, digits in n! are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “n factorial”, “permutations of n items”, “stirling”, “calculate factorial”, “find n!”.
Formula
Variables
- n — Number n
Worked example
With number n = 10, the calculator gives n! ≈ 3,628,800; digits in n! ≈ 7.
Frequently asked questions
What is the factorial calculator used for?
Compute n! and related counts. It helps with questions such as “n factorial”, “permutations of n items”, “stirling”.
What is the formula for the factorial calculation?
n! = fact(n). Digits in n! = floor(log10([n!]))+1. Here n is number n.
What inputs do I need for the factorial calculator?
You need number n. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the factorial calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the factorial result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.