Quick Answer: The probability of flipping exactly 10 heads in a row is (1/2)¹⁰ = 1 in 1,024 ≈ 0.098%. That sounds rare — but if you flip a coin many times, long streaks appear far more frequently than most people expect.
Calculating the Probability
Each coin flip is an independent event with 50% probability of heads. For a sequence of n consecutive heads, the probability is (1/2)^n:
| Consecutive Heads | Probability | Approximately 1 in... |
|---|---|---|
| 2 | 25% | 4 |
| 5 | 3.125% | 32 |
| 7 | 0.781% | 128 |
| 10 | 0.098% | 1,024 |
| 15 | 0.003% | 32,768 |
| 20 | 0.000095% | 1,048,576 |
Why Streaks Feel Rarer Than They Are
Our intuition severely underestimates how often long streaks occur in random sequences. Consider 200 coin flips. The probability of at least one run of 7 or more consecutive heads somewhere in those 200 flips is greater than 90%. Streaks are a natural, expected feature of any sufficiently long random sequence — not anomalies or signs of a pattern.
The Gambler's Fallacy Connection
Seeing 10 heads in a row makes many people feel strongly that tails is "due." This is the Gambler's Fallacy. The 11th flip is still exactly 50/50 — independent of all previous results. The streak influences our perception but has zero influence on the next outcome.