Math

Free Coin Flip Probability Calculator

Chance of getting exactly k heads in n flips.

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Inputs

Result

P(exactly 6 heads)

20.508%

P(at least one head)99.9023%
Expected heads5.00

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Short answer

Chance of getting exactly k heads in n flips.

What is the Coin Flip Probability Calculator?

Chance of getting exactly k heads in n flips.

How does the Coin Flip Probability Calculator work?

Enter the inputs above and read the result.

Formula

P(X=k) = C(n,k) × 0.5ⁿ

Variables

  • C(n,k)Combinations of n choose k

Explanation

Fair-coin flips follow a binomial distribution with p = 0.5.

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            Related concepts

            The Coin Flip Probability Calculator sits inside the Math Calculators hub, in the statistics & probability cluster. Describing data and quantifying uncertainty. Understanding the terms below makes the output easier to interpret and easier to compare against neighbouring measures.

            distributiondispersionsignificancesamplepopulationexpected value

            Practical use cases and industry applications

            Understanding Coin Flip Probability

            Chance of getting exactly k heads in n flips. Within math calculators, coin flip probability belongs to the statistics & probability cluster, where it shares terminology and assumptions with closely related tools.

            Learning how coin flip probability is calculated

            Fair-coin flips follow a binomial distribution with p = 0.5. Working through the variables one at a time — C(n,k) — makes the result reproducible by hand and easier to sanity-check.

            Using coin flip probability to make a decision

            Because outputs depend on the assumptions you enter, run more than one scenario before committing to a figure.

            How coin flip probability compares with related measures

            distribution, dispersion, significance, sample all describe adjacent aspects of statistics & probability. Comparing this calculator's output against those measures — using the related tools listed on this page — prevents a single metric from being read in isolation.

            Frequently asked questions

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