Combinations Calculator
Work out combinations or nCr instantly with this calculator that computes how many ways to choose items from a set, free in your browser.
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How to use this calculator
- Enter the total items (n) and chosen (r).
- Press Calculate.
How it works
Combinations (nCr) count selections where order doesn't matter: n! ÷ (r! × (n − r)!).
Worked example
5C2. = 10.
Common mistakes
- Using combinations when order matters — use a permutation then.
- Mixing up n and r; n is the total, r the number chosen.
Frequently asked questions
What is a combination?
A selection where order doesn't matter. The number of ways to choose r from n is nCr = n! ÷ (r! × (n − r)!).
Where are combinations used?
Lottery odds, choosing a team from a squad, or any ‘how many ways to pick’ question where arrangement is irrelevant.
Does order matter in combinations?
No — nCr counts selections where order is irrelevant. If order matters, use permutations (nPr), which give more arrangements.
Related tools
- Permutations Calculator
- Factorial Calculator
- Combinations with Repetition Calculator
- Permutations with Repetition Calculator
- Arithmetic Sequence Calculator
- Average (Mean) Calculator
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Cite this tool
Zerdly. (2026). Combinations Calculator. Retrieved from https://www.zerdly.com/tools/combinations-calculator/
Tip: Enter any known values to calculate the remaining results.
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