Is this coin flip truly random?

Yes. This coin flipper uses JavaScript's Math.random() function which provides a cryptographically sufficient pseudo-random number for each flip. Each flip has an independent 50/50 probability of landing heads or tails, just like a fair physical coin. The result of one flip does not affect the next.

What are the odds of flipping heads 10 times in a row?

The probability of flipping heads (or tails) 10 times in a row is (1/2)^10 = 1/1024, or approximately 0.098%. This is about 1 in 1,024. While rare, it will happen roughly once every 1,024 sequences of 10 flips. Each individual flip is still 50/50 regardless of what came before.

Why does my coin seem to land on heads more often?

With small numbers of flips, results can deviate significantly from 50/50. This is called short-run variance and is completely normal. Over hundreds or thousands of flips, the ratio will converge toward 50/50. This is an illustration of the Law of Large Numbers. Try flipping 100 or 1000 times using the multi-flip feature to see it in action.

Can I use this for making decisions?

Yes. A coin flip is a time-honoured method for making binary decisions. Some people find that the moment the coin is in the air, they realise which outcome they are hoping for, which helps clarify their actual preference. Either way, the result is genuinely random and fair.

What is the gambler's fallacy?

The gambler's fallacy is the mistaken belief that if heads has come up several times in a row, tails is now 'due'. In reality, each coin flip is independent. The coin has no memory. After 5 heads in a row, the next flip is still exactly 50/50. Past results do not influence future outcomes.

Coin Flipper

This coin flipper gives you an instant, genuinely random heads or tails result, useful for settling an argument, deciding who goes first, breaking a tie, or teaching probability without needing an actual coin. There is nothing to enter: click the coin or press the flip button and JavaScript's random number generator returns heads or tails with an even 50/50 chance every time, completely independent of whatever came before. To see probability play out over a larger sample, use the Flip 10 or Flip 100 buttons to run many flips in one go instead of clicking repeatedly. As you flip, a live scoreboard below the coin tracks your total number of flips, the count and percentage of heads, the count and percentage of tails, and your current streak, meaning how many times in a row the same side has come up. A scrolling flip history also records the full sequence so you can look back over individual results, and pressing the spacebar flips the coin without touching the mouse. The reset button clears every stat back to zero when you want to start a fresh run. Watching the heads and tails percentages settle towards an even split as your flip count grows is a simple, hands-on demonstration of the law of large numbers, and a useful reminder that a run of heads never makes tails more likely on the next flip.

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Heads

Total Flips

Heads

Tails

Current Streak

Flip history will appear here

About this coin flipper

This coin flipper generates a genuinely random result using JavaScript's Math.random() function. Each flip is independent, meaning the result of previous flips has no influence on the next one. The probability is exactly 50% heads and 50% tails on every single flip, just like a fair physical coin.

Probability reference

2 heads in a row: 25% (1 in 4)
5 heads in a row: 3.125% (1 in 32)
10 heads in a row: 0.098% (1 in 1,024)
20 heads in a row: 0.0001% (1 in 1,048,576)

The gambler's fallacy

It is tempting to think that after five heads in a row, tails is somehow "due". It is not. The coin has no memory, so the next flip is still exactly 50/50. This mistaken belief is called the gambler's fallacy, and the multi-flip feature above is a good way to see how short runs can look lopsided while the long-run average still settles near 50%.

Related tools

This coin flipper uses pseudo-random number generation. For cryptographic or security-critical applications, use a hardware random number generator.

Who this tool is for

This tool is for anyone who needs a quick, fair heads-or-tails result to settle a decision, play a game, or teach probability.

What this tool assumes

A fair coin with a 50/50 chance of each side.
It uses your browser's built-in random generator.
Each flip is independent of the last, so past results do not affect the next.

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