How to Calculate Combinations & Permutations — Step-by-Step Guide

Calculating Combinations & Permutations is straightforward when you know the formula. This page walks through each step, shows a worked example, and lets you verify your own numbers with our calculator.

Inputs

n (Total Items)*

r (Items to Choose)*

Calculation Type*

Results

Combination (nCr)ⓘ

Permutation (nPr)ⓘ

n! (Factorial of n)ⓘ

120

r! (Factorial of r)ⓘ