Coin Flip Probability Calculator

Your details

How many times the coin is flipped (n). Maximum 200 for chart performance.
The target number of heads (k) you want to calculate the probability for.
Choose whether to find the probability of exactly k, at least k, at most k, more than k, or fewer than k heads.
For a fair coin use 0.5. Adjust this for a weighted or biased coin (must be between 0 and 1).
ProbabilityPossible outcome
24.6094%

Probability of the selected outcome expressed as a percentage.

Odds (1 in X)1 in 4.06
Expected heads5
Standard deviation1.581
Probability (decimal)0.246094
24.6094% %
Very rare<1Unlikely1-10Possible10-50Likely50-90Near certain90+

24.6094% chance of exactly 5 heads in 10 flips.

  • With 10 flips and a 50% chance of heads per flip, getting exactly 5 heads has a 24.6094% probability.
  • The expected number of heads across 10 flips is 5.00, with a standard deviation of 1.58.
  • This outcome happens roughly once every 4.1 times you run 10 flips.
  • Your coin is fair (p = 0.5). Adjust the "probability of heads" input to model biased or weighted coins.

Next stepUse the distribution chart below to see how probability changes across all possible head counts for these settings.

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