Coin Flip Probability Calculator

Find the exact probability of getting a specific number of heads in a series of fair coin flips.

H
Number of Combinations-
Total Possible Outcomes-
Probability-
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How Coin Flip Probability Works

This is a classic binomial probability problem: each flip has two equally likely outcomes, and this calculator finds how many of the total possible sequences produce exactly the number of heads you specify.

Formula

Probability (%) = (C(n, k) ÷ 2^n) × 100, where n = number of flips, k = number of heads, and C(n, k) is the binomial coefficient ("n choose k").

How to Use This Calculator

Example

Flipping a coin 10 times, the probability of getting exactly 5 heads is 24.61% - the single most likely outcome, though still less than a coin flip's own 50/50 odds.

Frequently Asked Questions

How is coin flip probability calculated?

For a fair coin, each flip has a 50% chance of heads or tails; for multiple flips, probabilities of specific sequences or counts use the binomial probability formula.

What's the probability of getting all heads in 5 flips?

(0.5)^5 = 3.125%, since each flip is an independent event with a 50% chance.

Does a coin "remember" previous flips?

No — each flip is statistically independent. Getting several heads in a row doesn't change the odds of the next flip, a common misconception known as the gambler's fallacy.

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