Combination Permutation Calculator
Calculate permutations, combinations, repetition cases, and factorial from n and r.
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Calculate combinations, permutations, and repeated choices
Combination Permutation Calculator computes nCr, nPr, and repeated-choice counts from n and r. It is useful for probability exercises, raffle planning, team selection, test-case estimation, and any situation where the number of possible outcomes matters.
Useful For
- Calculate order-independent combinations
- Calculate order-sensitive permutations
- Compare repeated and non-repeated selections
Good To Know
Counting outcomes depends heavily on the conditions. Clarify order, repetition, exclusions, and min/max limits before relying on the result.
Result Check
Try an example first to understand the input flow. Before submitting, sharing, or copying important output, compare the result with the original source once more.
How It Works
Inputs are calculated or converted in the browser whenever possible. Compare important results with the original source before using them. Reviewed on Jul 1, 2026.
Combination and permutation checks
Problem type
- Use permutation when order matters and combination when it does not
- Check whether repeated selection is allowed
Inputs
- Review the relationship between n and r
- If r is greater than n, confirm whether repetition is allowed
Interpretation
- Results can become very large, so check digits and units
- For probability, compare favorable cases with total cases
Yes. Enter n and r to compare ordered permutations and unordered combinations.
It can also help check counts when repetition is allowed, depending on the selected mode.
Very large counts can run into display and browser performance limits, so treat them as reference calculations.