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Coin Flip: Heads or Tails
Press Flip for heads or tails. The page keeps a tally, so you can play best of three or flip a thousand coins at once.
Free tools that run in your browser. Nothing you type, open or create is uploaded to NerdBible or anyone else.
Hand the device to each person in turn. They press their own name, read it, then press Hide before passing it on. Only one match is ever on screen.
Every result comes from your browser's cryptographic random number generator, with rejection sampling so no number is even slightly more likely than another. Nothing is sent anywhere.
How to use it
- Pick a tab: Number, Dice, Coin, Letter, Teams or Secret Santa.
- Set the range, the dice and modifier, the number of coins, the letters, or the list of names.
- Press the button. Press it again for a fresh result; dice and coins keep a running record.
- For Secret Santa, add any pairs who should not draw each other, press Draw names, then pass the device round so each person reveals only their own match.
Questions
Is an online coin flip fair?
This one is. It uses cryptographic randomness with exactly two equally likely outcomes, so neither heads nor tails is favoured.
Why did I get heads several times in a row?
Streaks happen in genuine randomness. In 20 fair flips, a run of four or more of the same side is more likely than not.
Can I flip more than one coin?
Yes. Set coins per flip up to 1,000 and the result shows how many came up heads and tails.
About this tool
A fair 50/50
Each flip comes from your browser's cryptographic random number generator, so heads and tails are exactly equally likely and each flip has no memory of the last. Studies of real coin tosses have found a small bias towards the side that started facing up; a virtual coin has none.
- One coin or many. Set coins per flip anywhere from 1 to 1,000 to see how the share of heads settles near half as the count grows.
- Running tally. Heads, tails and the share of heads are counted until you reset, which settles best of three or best of five.
- No pattern to beat. After five heads in a row, the next flip is still a 50/50. Streaks are normal in random sequences.
Uses
Deciding who goes first, choosing between two options, or showing a class how probability behaves over many trials. For more than two choices, use the spinner wheel or the random number tab.
Nothing is stored; the tally resets when you close the page.
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