How to flip a coin online
- Choose how many Coins to toss: 1, 3, 5, 10, 100, or Custom for any number from 1 to 100.
- Press Flip, or press the Space or Enter key. A single coin spins in the air and lands on heads (the crown) or tails (the star). Several coins appear as a grid of H and T results with the heads and tails count for that throw.
- Watch Your tally: heads, tails, total flips, the percentage of each, the current streak and the longest streak of each side. The strip below it shows your last 50 results, newest first.
- Switch on Yes/no mode to ask a question: heads means yes, tails means no. Only the wording changes; the coin is the same.
- Press Reset to clear the tally and history and start again.
Why this coin flip is fair
Each coin is decided by crypto.getRandomValues(), the secure random generator built into your browser, which is seeded from your operating system's entropy source. The tool asks for one random byte per coin and looks at a single bit of it: 0 is heads, 1 is tails. Every possible byte is equally likely, and exactly half of the 256 values have that bit set, so heads and tails each have a chance of exactly 1 in 2. There is no rounding and no remainder trick that could tilt the odds, which is a common flaw when random numbers are squeezed into a range.
The result is chosen before the animation starts. The spin is only for show, and you cannot influence it by pressing at a particular moment.
Every flip is also independent. The coin has no memory, so after five heads in a row the next flip is still 50/50. Believing that tails is now "due" is known as the gambler's fallacy. Streaks feel surprising, but they are a normal part of randomness, as the table shows.
Coin toss probabilities
| Event | Chance | About |
|---|---|---|
| Heads on one flip | 1 in 2 | 50% |
| 2 heads in a row | 1 in 4 | 25% |
| 3 heads in a row | 1 in 8 | 12.5% |
| 5 heads in a row | 1 in 32 | 3.1% |
| 10 heads in a row | 1 in 1,024 | 0.1% |
| At least one head in 3 flips | 7 in 8 | 87.5% |
| Exactly 50 heads in 100 flips | about 1 in 12.6 | 7.96% |
Exactly 50 heads in 100 flips is the single most likely outcome, yet it happens less than 8% of the time; results between 40 and 60 heads are far more typical than a perfect split. Long streaks are common too: in 100 flips, the longest run of the same side is usually between 5 and 8, and about 7 on average. Flip 100 coins a few times and compare your longest streaks with those numbers.
Do real coins land 50/50?
Very nearly, but perhaps not exactly. Research by Persi Diaconis, Susan Holmes and Richard Montgomery (2007) suggests a slight bias toward the side facing up at the start of a toss, about 51%. A 2023 study by František Bartoš and colleagues, with about 350,000 tosses, found that coins landed on the same side they started on roughly 50.8% of the time. A virtual coin has no starting side, no spin and no thumb, so it does not have this bias.
What people use a coin toss for
- Making a decision between two options, or settling who goes first. Yes/no mode makes the answer read naturally.
- Sport: the referee's toss decides kick-off or ends in football, and in cricket the winning captain chooses to bat or bowl.
- Games that need a 50/50 choice, and a "best of 3" when one toss feels too final.
- Teaching probability: flip 100 coins and see how the share of heads wobbles around 50%, then reset and do it again.
Need more than two outcomes? Roll dice or pick a number in any range with the random number generator, or put names on the spin the wheel name picker. For yes, no or maybe, or a best of 3 that runs by itself, spin the yes or no wheel. Find more calculators and generators among the everyday tools.
Privacy
Every flip happens in your browser and nothing is sent to a server. Your tally, your last 50 results and your settings (number of coins, yes/no mode) are kept in this browser's local storage, so they survive a reload. Reset clears the tally and history.
Frequently asked questions
Is an online coin flip fair?
This one is. It uses your browser's cryptographically secure random generator and one random bit per coin, so heads and tails each have exactly a 50% chance, and every flip is independent of the ones before.
What are the odds of getting heads?
1 in 2, or 50%, on every flip. The odds of several heads in a row halve with each flip: 1 in 4 for two, 1 in 8 for three and 1 in 1,024 for ten.
Can I flip more than one coin at once?
Yes. Choose 3, 5, 10 or 100 coins, or Custom for any number up to 100. You see every result as H or T, the heads and tails count for that throw, and all of them are added to your tally.
What does "best of 3" mean, and how do I do it here?
Best of 3 means the first side to win two tosses wins. Choose 3 coins and press Flip once: the side that appears two or three times is the winner, which gives the same result as tossing until one side has two wins.
Is heads more likely than tails?
Not with this tool: both sides have exactly the same chance. With a real coin, studies suggest a slight tendency, about 51%, to land on whichever side was facing up when it was tossed, so neither heads nor tails is favoured in itself.
Does the tool store my results?
Only in your own browser. The tally, the last 50 results and your settings are saved in local storage on this device so a reload keeps them, and Reset deletes the tally and history. Nothing is uploaded.
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