Flip a coin online: heads or tails

How to flip a coin online

1. Click “Flip the coin”, or the coin itself.
2. The coin spins in the air, lands and settles on heads or tails: the result appears once it has landed.
3. Flip again as often as you like: the tool counts the flips of the session and keeps the last 30 under the result.

To decide who goes first, open “Who goes first?” and type a name for each side, for example Alice for heads and Ben for tails: the result tells you straight away who wins. It is free, with no sign-up, and nothing is sent.

Flip a coin many times

The “Flip many times” tab flips the coin from 1 to 10,000 times at once. It shows the number and percentage of heads and tails, the longest run of each side with its position, and the first 200 flips in order. The 10, 100, 1,000 and 10,000 shortcuts let you compare a small series with a very large one in seconds.

It is a simple way to see the law of large numbers at work, in class or out of curiosity: over 10 flips, the gap from 50% is often large; over 10,000, the share of heads stays between 49% and 51% in more than 95% of cases.

Is it really 50/50?

Here, yes. Each flip uses your browser’s crypto.getRandomValues function, the random number generator also used to create encryption keys: heads and tails have exactly the same chance, and a flip never depends on the previous ones. We checked it over 40,000 flips: about 20,000 of each, with normal variation for chance.

A real coin is slightly less perfect. In 2023, a team of researchers flipped coins 350,757 times: they landed on the side they started from 50.8% of the time, as mathematician Persi Diaconis had predicted. The gap is small, but it is real: a coin flipped heads up lands heads a little more often.

What probability says

• Over 10 flips, you get exactly 5 heads and 5 tails only one time in four (24.6%).
• Over 100 flips, the number of heads lands between 40 and 60 in 96.5% of cases.
• Over 1,000 flips, it lands between 469 and 531 in 95.4% of cases: the percentage gap shrinks as the number of flips grows.
• Runs are longer than people expect: over 100 flips, you see the same side at least 6 times in a row in 81% of cases.
• 10 times in a row the side you picked: a 1 in 1,024 chance, about 0.1%.

After five tails in a row, the chance of heads on the next flip is still 50%: the coin has no memory. Believing that one side is “due” after a long run is a classic mistake known as the gambler’s fallacy.

Which side is heads?

Heads is the side with a portrait, traditionally the head of a ruler; tails is the other side, the reverse. On US coins, heads is the side with the president’s profile, such as George Washington on the quarter; on British coins, it is the side with the monarch’s portrait.

On the tool’s coin, it is spelled out: HEADS on one side, with a face, and TAILS on the other, with a stack of coins.

When to flip a coin

• In sports: a coin toss decides who kicks off or chooses an end in football and soccer, who bats first in cricket, and who serves first in tennis.
• To decide who goes first in a board game, who drives or who picks the movie.
• To settle between two options that are roughly equal. A well-known tip: if the result disappoints you, you now know what you really wanted.
• Best of three: flip three times, and the first side to come up twice wins.

More free tools

• the random name picker picks names, spins a wheel, makes teams and rolls dice;
• the percentage calculator works out a share, an increase or a decrease in one click;
• the AI lottery number generator creates random lines and shows the real odds of each game.