What this calculator does
Most math & education tools bury the answer under ads and jargon. The combination calculator shows the number first, the breakdown next, and the assumptions in plain language.
Combinations count unordered selections.
How to use the Combination Calculator
- Enter your values in the fields on the left.
- Results update automatically.
- Use action buttons to copy, share or print.
The formula
C(n,r) = n! / (r!(n−r)!)
Worked example
C(10,3) = 120.
Common mistakes
- Confusing with permutations
- Off-by-one in r
- Overflow with big n
When to use it
Use for lotteries, teams, subsets.
Pro tips for the Combination Calculator
- Bookmark this page: the URL and inputs are all you need to reproduce the exact result later.
- Save your favorite scenarios by clicking the star icon — they're stored locally, no account needed.
- For big decisions, run best-case, expected, and worst-case scenarios and compare the breakdowns side by side.
Frequently asked questions
›Pascal's triangle?
Rows are combinations.
›Symmetric?
C(n,r) = C(n,n−r).
›Multinomial?
For more than two categories.
›Poker hands?
C(52,5) = 2,598,960.
›Binomial theorem?
(a+b)^n uses combinations.
›Can I embed the Combination Calculator on my site?
Embedding isn't public yet, but you can link directly to this page — the URL is stable and shareable.
›Is the Combination Calculator free to use?
Yes. Every calculator on CalcPilot, including the Combination Calculator, is free with no sign-up, no watermark, and no export limit.
Embed this calculator
Drop the Combination Calculator into your own site or blog post. Free to use — a small “Powered by CalcPilot” link is appreciated.
<iframe src="https://calcpilot.tools/calculators/combination-calculator?embed=1" width="100%" height="720" style="border:1px solid #e5e7eb;border-radius:12px;max-width:720px;" loading="lazy" title="Combination Calculator — CalcPilot"></iframe>Related calculators
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