# Combinations Calculator

> Calculate nCr combinations for unordered selections. Supports choices with or without repetition allowed.

**URL:** https://www.calculatoranswers.com/combinations-calculator
**Category:** Education

## Quick Answer

Calculate nCr combinations for any pool of items. Enter the pool size and selection count to find the number of unique unordered groups.

## Definition

A combinations calculator is a mathematical counting utility that computes the number of unique subsets of size r that can be chosen from a larger pool of n distinct elements. In combinations, the selection order is completely ignored. The calculator evaluates combinations using the standard binomial coefficient formula and applies symmetry adjustments to optimize calculation speed and accuracy. It is widely used in algebra, probability theory, lottery designs, card games, and scheduling combinations.

## How to Use

1. **Select repetition setting** — Choose whether items can be selected multiple times in a single combination.
2. **Enter the pool size (n)** — Type the total number of distinct items available in the starting set.
3. **Enter the choice size (r)** — Input the number of items to select for each group.
4. **Read the combinations count** — View the calculated number of unordered combinations alongside the formula.

## Disclaimer

This calculator provides estimates for educational and planning purposes. Always consult a qualified professional for specific advice on financial, medical, legal, or other regulated decisions.

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