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Coin Flip Simulator
Flip many coins at once and watch probability at work: the share of heads gets closer to 50% the more coins you flip, while long streaks turn up more often than most people expect.
Flipping… Tap the coin or press Flip
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Longest streak
Difference from 50%
flips: (%) · (%)
Press Space to flip. The side is drawn with your browser’s secure random number generator before the coin moves.
More than two options? Try the Spin the Wheel, the Random Number Generator or the Dice Roller.
About the Coin Flip
Flip a virtual coin when you need a fair 50/50 decision. Each toss is drawn with your browser’s secure random number generator before the coin spins, so the animation never decides the result. Play a single flip, a best of 3, 5 or 7 series, or flip up to 10,000 coins at once to see how the share of heads settles near 50% and how long the longest streak gets. Your last 60 flips and their totals are kept in your browser.
How to use it
- 1 Choose Flip a coin, Best of or Many coins.
- 2 Call heads or tails if you like.
- 3 Tap the coin, press Flip or press the space bar.
- 4 Read the result and your running heads and tails count.
Frequently asked questions
Why isn’t it exactly 50% heads?
Random results wobble. With 100 flips, anything from about 40 to 60 heads is normal. With 10,000 flips the share is usually within one percentage point of 50%. This is the law of large numbers.
How long a streak should I expect?
In 100 flips the longest run of one side is usually 5 to 8. In 1,000 flips it is usually 8 to 12. Streaks are normal in random data, which is why people often think fair results look “too streaky”.
Can I use this for a class experiment?
Yes. Ask students to predict the number of heads and the longest streak, then flip 10, 100 and 1,000 coins and compare. Each run is new and independent.
Is this coin flip really random?
Yes. Each flip uses crypto.getRandomValues, the browser’s secure random number generator, so heads and tails each have exactly a 50% chance and no flip depends on the ones before.
Is an online coin flip as fair as a real coin?
It is fairer. Real coins are very slightly biased towards the side that faces up when flipped (about 51% in a 2023 study of 350,000 flips). The virtual coin has no such bias.
What are the odds of getting heads 3 times in a row?
1 in 8 (12.5%). Each flip halves the chance: 2 in a row is 1 in 4, 5 in a row is 1 in 32 and 10 in a row is 1 in 1,024.
After several tails, is heads more likely?
No. The coin has no memory, so heads is still exactly 50% on the next flip. Believing otherwise is called the gambler’s fallacy.
Can I use it to decide who goes first?
Yes. Let one person call heads or tails before the flip. For more than two people or options, use the spin the wheel tool instead.
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