Flip a virtual coin with a spin animation, a running score and a batch mode for statistics.
A coin flip settles arguments because both outcomes are equally likely and everyone can see it happen. This tool reproduces that: one big button, a coin that spins for about 800 milliseconds, and a result that was already decided the moment you clicked — the animation exists for the drama, not for the maths. Heads and tails each have exactly a 50% chance on every single flip.
The draw itself uses crypto.getRandomValues, the browser cryptographic generator, with rejection sampling so the two outcomes are perfectly balanced with no modulo bias. A real coin is not quite this fair: physics studies have measured a tiny bias toward the side that was facing up when the coin was tossed. A properly implemented digital flip has no such memory — each flip is independent, and no streak of heads makes tails any more likely on the next click. That is the gambler fallacy, and the running score is a good place to watch it fail.
The scoreboard keeps heads, tails and the total for your session, and the strip shows the last 20 results in order so you can see streaks for what they are. The batch mode flips up to 1,000 times instantly and reports the percentages, which is the fastest way to see the law of large numbers in action: ten flips can easily land 7-3, while a thousand flips almost always sit within a couple of points of 50/50. Everything runs in your browser, nothing is sent to a server, and the score resets when you reload the page.
Yes. Each flip uses the browser cryptographic random generator with rejection sampling, so heads and tails have exactly the same probability and every flip is independent of the previous ones.
No. The coin has no memory: the next flip is still 50/50. Expecting a correction after a streak is the gambler fallacy, and the batch mode is a quick way to see how common streaks actually are.
In practice, yes. Real tosses carry a small measurable bias toward the face that started up, and they can be influenced by how you throw. A cryptographic draw has neither problem.
It flips up to 1,000 coins at once and shows the percentages — useful for classes, probability demonstrations and for seeing how results converge to 50/50 as the number of flips grows.
No. The flips, the score and the history live only in this page, in JavaScript, on your device. Nothing is transmitted or stored, and reloading clears everything.
Vai.la turns any URL into a short link with click statistics, QR Code and your own biolink.
Vai.la is not responsible for how the tools are used or for decisions made based on their results.