❗ Factorial Calculator

Calculate factorials, permutations, and combinations with ease. Supports large integer arithmetic for accurate results.

r (for Perm/Comb)

Factorial n! Permutation P(n,r) Combination C(n,r)

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How to Use the Factorial Calculator

Using the Factorial Calculator is straightforward:

Enter Your Values
Input the required numbers and parameters into the calculator fields. Each field is clearly labeled — simply type your values or use the spinner controls to adjust them.
Configure Options
Select any additional options such as computation mode, currency, time period, or precision level. The calculator updates automatically as you change values.
View the Results
The calculated result is displayed instantly with clear formatting. You can Copy the result to your clipboard or adjust input values to see how different scenarios affect the outcome.

Factorial (n!) is the product of all positive integers less than or equal to n. E.g., 5! = 5×4×3×2×1 = 120. 0! is defined as 1.

P(n,r) counts the number of ways to arrange r items from n distinct items, where order matters. Formula: P(n,r) = n!/(n-r)!

C(n,r) counts the number of ways to select r items from n items, where order doesn't matter. Formula: C(n,r) = n!/[r!(n-r)!].

0! = 1 is a mathematical convention that ensures formulas like permutations and combinations work correctly at boundary values.