OneTaskBy Tim King · Updated
3D Coin Flip
Toss a Real Physics Coin for Heads or Tails in Your Browser
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How the 3D Coin Flip works
This 3D coin flip throws a physics-driven coin for a fair heads or tails. Press Flip or click the table and a gold coin is thrown into the air with a random spin, lands on the felt, bounces off the rim if it strays, and comes to rest showing heads or tails. Toss one coin for a quick decision or up to twelve at once, switch the faces to Yes and No, and watch the running tally, percentages and longest streak build up across tosses. Drag to orbit, scroll to zoom, Save PNG to keep the result.
How the 3D coin flip works
A normal online coin flipper picks heads or tails with a random number generator and shows you a picture. This one throws a real coin. The coin is a thin cylinder with a face printed on each side, dropped into a 3D physics engine that runs entirely in your browser, and it tumbles, collides with the table and the other coins, and settles the way a real coin does. The result is read from whichever face ends up pointing upward once the coin has stopped moving.
Is it fair? Every toss starts from a random orientation, with a random upward speed and a random spin on every axis, so after the coin has bounced a couple of times the outcome is as unpredictable as a real flip. Over many tosses the percentages settle towards fifty-fifty, and the tally under the table lets you watch that happen. If you need a coin that is provably fair for something that matters, the plain Coin Flip tool uses the browser's cryptographic random generator; this one is for when you want to see it land.
Multiple coins. Set Coins per toss to anything up to twelve and they are all thrown together. The status line lists each result in order and the stats count every coin, so tossing twelve coins ten times gives you a hundred and twenty samples in under a minute. The longest streak counts consecutive identical results across every coin and every toss since the page was last reset.
Yes / No. Choose Yes / No under Show as and the faces are relabelled Y and N, which is handy when you are using the coin to make a decision rather than to settle a bet. Restart clears the tally and starts fresh. Nothing is sent anywhere; the physics, the rendering and the counting all happen in the page.
FAQ
Can the coin land on its edge?
In principle, but the coin is thin and the felt is soft, so it has not happened in testing. If a coin were still upright when it stopped, the reading would take whichever face is nearer to pointing up.
Why does the tally not match exactly fifty-fifty?
Because it is a random process. After a hundred tosses a 45/55 split is unremarkable; the percentages converge slowly and the longest streak of six or seven is normal. Keep tossing and it drifts towards half.
Is it running slowly on my phone?
Twelve coins is the heaviest setting. Drop to a few coins, or close the other tabs; the physics runs at a fixed step so a slow device shows fewer frames rather than changing the result.
Can I use it to settle something serious?
Use the plain coin flip for that, which uses the browser's cryptographic random generator. This one is unpredictable in practice but is a physics simulation, not a proof of fairness.
See also: all Simulations & Screensavers tools, Images, Audio, Video & Screen, PDF, SVG, Generative Art, Chart Makers, 3D Model Viewers, Drawing Pads, Mockups & 3D Making, Diagram Makers, 3D Science, Tracker Music.
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