The Combination Calculator is a free online tool that helps you calculate the number of possible selections or groups when order does not matter. Using the formula C(n, r) = n! / [r! (n – r)!], this calculator instantly provides accurate results for given values of n (total items) and r (selected items). It is widely used in probability, statistics, and combinatorics to solve problems involving group formation, lottery chances, or data sampling. Designed to be fast, mobile-friendly, and WordPress-safe, this calculator is perfect for students, teachers, and professionals who need quick and reliable combination results.