Permutation & Combination Calculator

Calculate nPr, nCr, and factorials with step-by-step solutions

Factorial Calculator

n! =

Frequently Asked Questions

What is the difference between permutation and combination?
Permutation (nPr) considers order (ABC ≠ BAC), while combination (nCr) does not (ABC = BAC). Use permutations when order matters, combinations when it doesn't.
What is a factorial?
A factorial (n!) is the product of all positive integers from 1 to n. 0! = 1, 5! = 120.
What is the maximum n value?
JavaScript can safely compute factorials up to 170! (≈ 7.26 × 10³⁰⁶). Beyond that, values exceed the maximum safe integer.