Coin Flip Probability Calculator
Calculate the probability of getting a specific number of heads (or tails) in a series of coin flips.
Probability
Coin Flip Probability uses the binomial distribution to calculate the likelihood of outcomes.
Exactly k heads in n flips:
P(X = k) = C(n,k) × 0.5ⁿ
Where C(n,k) = n! / (k! × (n-k)!)
At least k heads in n flips:
P(X ≥ k) = sum of P(X = i) for i = k to n
Examples:
- P(exactly 3 heads in 5 flips) = 31.25%
- P(at least 1 head in 3 flips) = 87.5%
- P(all heads in 10 flips) = 0.098%
Fun fact: The probability of heads is always 50% on each flip, regardless of previous results. This is called the gambler’s fallacy.