Flip a coin
Click the coin or the button to flip it. The coin spins in 3D and lands on heads or tails with exactly 50% odds each. A counter tracks heads, tails and your current streak, and you can simulate up to 100,000 flips at once. Each flip is independent of the one before.
- ✅ Free
- 🔒 No sign-up
- 📱 Works on mobile
- ⚡ Instant results
🔒 Everything runs in your browser. Your data and files never leave your device.
📌 Key facts
- A fair coin lands on heads or tails with exactly 50% odds each, or 1 in 2.
- The odds of n heads in a row are (1/2) to the power n, so 10 heads in a row happens 1 time in 1,024.
- Flips are independent: after 5 heads, the next flip is still 50% heads.
- In 100 flips, the longest run of one side averages about 6 to 7 flips.
- A coin flip settles only two options; use dice or a wheel when you have more choices.
A truly 50/50 coin
Each flip reads a random bit from your browser's cryptographic generator. There is no weighted coin and no memory: the previous result never affects the next one.
\[ P(\text{heads}) = P(\text{tails}) = \dfrac{1}{2} = 50\% \]
After ten heads in a row, the chance of an eleventh is still 50%. Believing otherwise is the gambler's fallacy.
Streaks and many flips
| Streak of | Probability |
|---|---|
| 2 heads in a row | 25% |
| 3 heads in a row | 12.5% |
| 5 heads in a row | 3.1% |
| 10 heads in a row | 0.1% |
Over a few flips the gap can be wide (7 heads out of 10 is normal). With 100,000 flips the share of heads gets close to 50%: that is the law of large numbers.
When to flip a coin
- Settle a tie between two options.
- Decide who kicks off or who serves first.
- Show probability in a math class.
For a big decision, do not let a coin decide: if you are disappointed by the result, you just learned what you wanted.
Flip a coin: the odds you should know
When you flip a coin, each toss has two equally likely outcomes. So heads has a probability of 1/2, and so does tails.
Streaks, however, drop off fast. For example, three heads in a row shows up 1 time in 8. Finally, ten heads in a row happens only 1 time in 1,024.
| Run of one side | Probability |
|---|---|
| 2 in a row | 25% |
| 3 in a row | 12.5% |
| 5 in a row | 3.1% |
| 10 in a row | 0.098% |
Still, a long streak is not a red flag. In 100 flips, a run of 6 or 7 is normal.
Flip a coin and the gambler's fallacy
Many people believe tails is "due" after a long streak of heads. That is the gambler's fallacy. A coin has no memory.
Therefore, every flip starts fresh. Even after nine heads, the tenth flip is still 50% heads and 50% tails.
To see this yourself, run a big batch with the tool. Then look at the counter: the share of heads and tails moves toward 50%, but the raw gap between them does not shrink to zero. The proportions converge, not the totals.
When to flip a coin, roll dice or spin a wheel
A coin works for two options only. If you have three or more, switch tools.
- For six options, use the dice roller.
- For an exact number, try the random number generator.
- For a list of names or ideas, spin the wheel spinner.
- For a head-to-head duel, play rock paper scissors.
Finally, call your side before the flip. That prevents arguments, because a side called after the fact counts for nothing.
Flip a coin: call it before you toss
When you flip a coin, the result is fair only if everyone accepts the rule beforehand. So settle three points before you click.
- Who picks a side, and when they call it.
- How many flips count: just one, or best of three.
- What each side wins.
For example, two friends arguing over a movie can flip a coin, best of three. That way, chance decides and nobody holds a grudge. Also, the counter in the tool tracks heads and tails, which removes doubt.
Finally, if you feel let down by the result, you may learn what you really wanted. Many people discover their preference the moment the coin lands. That is why flipping a coin also helps with a personal decision you cannot make.
Flip a coin thousands of times
A mass simulation shows the law of large numbers. With 10 flips, you might see 7 heads. With 10,000 flips, the share of heads moves close to 50%.
Next, compare several runs. You will notice that the gap in percentage points shrinks as the number of flips grows. For example, in 100 flips a 10-point gap is common, while in 10,000 flips it is very rare.
So you can use this tool in a math class to illustrate probability, frequency and expected value, and every time you flip a coin the result teaches the same lesson.
3 real-life examples
Settle where to eat
You flip: "Tails". Each option had a 50% chance and the decision took one second.
A heads streak
You get 5 heads in a row. That had a 3.1% chance, but the sixth flip is still 50/50.
A thousand flips
You simulate 1,000 flips and get 512 heads and 488 tails. That gap is normal, and the share approaches 50% as the number of flips grows.