Coin Flip Probability Calculator

Find the chance of exactly k heads in n flips.

Probability (%) 24.609

Formula: P = C(n,k) × 0.5ⁿ

Step-by-step with your numbers:
1. Values used:
2. Number of flips = 10
3. Number of heads = 5
4.
5. Probability = 24.609%
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The chance of getting exactly a number of heads in fair coin flips.

The math behind it

P = combinations C(n,k) × (1/2)ⁿ for a fair coin.

Worked example

Exactly 5 heads in 10 flips → 24.6%.

FAQ

At least k?

Sum the probabilities for k, k+1, … up to n.