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Combination Calculator

A combination is a selection where order does not matter. Enter the total number of items n and how many you are choosing r to get nCr, “n choose r”, exactly — plus the count when items can be chosen more than once and the matching number of permutations.

Quick examples
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Combinations (nCr)2,598,960
Formula
52! ÷ (5! × (52 − 5)!) = 52! ÷ (5! × 47!)
With repetition allowed
3,819,816
Permutations (nPr), if order mattered
311,875,200

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      Formula

      nCr = n! ÷ (r! × (n − r)!)
      With repetition allowed: C(n + r − 1, r)
      nCr = nPr ÷ r!

      How to use it

      1. Enter the total number of distinct items, n.
      2. Enter how many are chosen, r.
      3. Read nCr. Results over 30 digits are shown in scientific notation.

      Worked examples

      Five-card hands from a 52-card deck

      Combinations (nCr)
      2,598,960
      Permutations (nPr), if order mattered
      311,875,200

      Choosing 6 numbers from 49

      Combinations (nCr)
      13,983,816

      A committee of 3 from 10 people

      Combinations (nCr)
      120
      Formula
      10! ÷ (3! × (10 − 3)!) = 10! ÷ (3! × 7!)
      With repetition allowed
      220

      Lottery and card odds

      Choosing 6 numbers from 49 can be done 13,983,816 ways, so one ticket has a 1 in 13,983,816 chance of matching all six. Powerball’s five white balls from 69 give 11,238,513 combinations; multiplied by the 26 possible Powerballs that is 1 in 292,201,338 for the jackpot.

      A standard deck has 2,598,960 different five-card hands.

      Useful properties

      Choosing r items to take is the same as choosing n − r to leave behind, so nCr = nC(n − r): 52C5 = 52C47.

      With repetition allowed — three scoops from 10 ice-cream flavors, where a flavor can be picked twice — the count is C(10 + 3 − 1, 3) = 220 instead of 120.

      Questions people ask

      What is 52 choose 5?

      2,598,960 — the number of five-card poker hands.

      What is 10 choose 3?

      120, from (10 × 9 × 8) ÷ (3 × 2 × 1).

      What is the difference between a combination and a permutation?

      A combination ignores order; a permutation counts each ordering separately. Three items chosen from ten make 120 combinations but 720 permutations.

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