Coin Flip
Heads or tails: flip one coin or many, with a fair result every time.
Coin Flip: the tool
Flip
From 1 to 1,000.
Result
Press Flip. Heads and tails have exactly the same chance, and a flip does not depend on the one before.
Flip a coin when you need a quick decision or a fair way to start a game. Press the button and get heads or tails. You can flip up to a thousand coins at once and see how many came up each way, and a tally keeps count while the page is open.
How it works
Each flip asks your browser's cryptographic random generator for a single unpredictable bit: zero is heads, one is tails. The two outcomes have exactly the same probability, and a flip has no memory. After five heads in a row the next flip is still an even chance, because nothing in the process knows what came before. Believing otherwise is the gambler's fallacy.
A real coin is a little less perfect. A careful study that filmed real coin tosses found that a coin tends to land on the side it started on slightly more than half the time, roughly 51 percent. The effect is tiny, and it is one reason a virtual flip is, if anything, fairer than a thumb-flicked coin: this one has no starting side.
When you flip many coins, the counts hover around an even split but are rarely exactly even. Flip a hundred and you will usually see between 40 and 60 heads. That spread is expected, and it grows smaller in proportion as you flip more. The tally under the controls shows the totals since you opened the page, and the strip of letters shows the last flips in order.
How to use it
- Leave the number of coins at 1 for a single flip, or enter more to flip several at once.
- Press Flip. The coin turns over and the result is shown in large type.
- Press Flip again as often as you like. Each flip is independent of the last.
- Use Reset the count to clear the tally and start counting again.
Example
Ten flips with a fixed sequence, shown as letters in the order they happened, with the count of each side. Your own flips will differ.
What was set
- Coins
- 10
What came out
- In order
- H T H T H H T H T H
- Count
- 6 heads, 4 tails
Good to know
- You can flip from 1 to 1,000 coins at a time. Pictures of the individual coins are shown up to 30 at once; beyond that you get the counts.
- The count and the history exist only while the page is open. They are not saved and not sent anywhere.
- This is a fair way to settle small matters. Do not use it for gambling, and do not treat the result as advice about an important decision.
Questions people ask
Is the coin flip really 50/50?
Yes. Each flip uses one bit from the browser's cryptographic random generator, and heads and tails are equally likely. Unlike a physical coin, which can have a small bias, this one has no weight, no starting side and no wear.
Why did I get five heads in a row?
Because that is what random flips do. The chance of five heads in a row is 1 in 32, so over many flips you should expect it to happen now and then. Streaks are a sign of randomness, and a generator that never produced them would be the suspicious one.
Does the previous result change the next flip?
No. Each flip is completely independent. After a long run of heads, tails is not due, and heads is not hot: the chance of each stays at one half.
Can I flip more than one coin?
Yes. Enter the number of coins and press Flip. You see how many came up heads and how many tails, and for up to 30 coins you also see each one.
Is the result stored or shared?
No. Nothing leaves your browser. The running tally is kept in the page's memory only and disappears when you close or reload it.