Coin Flip
Flip a fair coin once or many times and count heads and tails.
About the Coin Flip
Flip one coin or many at once. With several flips you see the count of heads and tails and the longest streak.
Each flip uses your browser's cryptographically secure random number generator, so heads and tails are equally likely and independent. Over many flips the share of heads approaches 50%, but streaks are normal: in 100 flips a run of 6 or more is likely.
The formula
P(heads) = ½ for each flip
Worked example
Flipping 100 coins
- Expect about 50 heads, but anywhere from about 40 to 60 is common
- A streak of 6 or more in a row usually appears
Questions people ask
Is a real coin fair?
Nearly; studies suggest a slight bias toward the side facing up at the start.
Do past flips affect the next?
No, that's the gambler's fallacy.
What are the odds of 3 heads in a row?
1 in 8 (½ × ½ × ½).