Combination Calculator
Enter n and r to instantly compute C(n,r) — the number of unordered combinations — with full factorial working shown.
Combination Calculator — C(n, r)
Quick Examples
Result
Enter n and r to see the result
C(n, r)
Step-by-step working
Formula:
C(n,r) = n! / (r! × (n−r)!)
Substituted:
Numerator:
Denominator:
Result:
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Summary
Enter n and r to instantly compute C(n,r) — the number of unordered combinations — with full factorial working shown.
How it works
- Enter n — the total number of items in the set.
- Enter r — the number of items you want to choose.
- The calculator applies the formula C(n,r) = n! / (r! × (n−r)!).
- The result and a step-by-step factorial breakdown appear immediately.
- Use the Copy button to copy the result to your clipboard.
Use cases
- Calculate lottery odds (e.g. how many ways to pick 6 numbers from 49).
- Count hand combinations in card games like poker.
- Determine the number of possible teams from a group of players.
- Solve combinatorics homework problems with shown working.
- Compute binomial distribution coefficients for statistics.
- Find the number of committee compositions from a candidate pool.
- Evaluate sample sizes for experimental design.
- Check answers for nCr calculations in probability courses.
Frequently Asked Questions
Last updated: 2026-06-13 ·
Reviewed by Nham Vu