Coin Flip Probability Calculator

Odds of getting your run of heads, tails, or a mix across any number of fair flips.

Number of flips

Exactly how many heads

P(exactly k heads) %

24.61

Last updated: 2026-08-31

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FAQ

Is a coin flip really 50/50?

Physical coins land on the side they started slightly more often than 50%, but for any practical purpose a fair-coin model of 50/50 is right.

What are the odds of 10 heads in a row?

One in 1,024 — about 0.1%. Streaks feel surprising, but any specific sequence of ten flips has exactly the same chance.

What formula does this use?

The binomial distribution: n choose k divided by 2 to the power n, where n is flips and k is heads.

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