Random Coin Flip
Heads or tails, instantly.
Built and maintained by Paul Clark, Redmoon Software · Last checked
Settle who kicks off, break a tie, or run a probability demo with a single tap. Flip one coin for a big HEADS or TAILS, or flip up to 100 at once to get a full tally plus the longest streak in the batch. Each flip is an exact, cryptographically secure 50/50, so neither face is ever favored.
Set. Choose how many times to flip (1 for a single flip).
Click Flip the coin to see a result.
Options
Recent results
- No history yet.
How it works
- Set. Choose how many times to flip (1 for a single flip).
- Flip. Click "Flip the coin" to see the result(s).
- Reflip. Click again anytime for a fresh flip.
- Review. Scroll the history list to compare earlier flips and batches.
About the Random Coin Flip
Flip once, or flip a hundred times
A single flip is what most people come for, but the Count option goes up to a hundred in one go and returns rather more than a list of results: the totals for each face, and the longest run of the same face in the sequence.
That longest-run figure is the interesting one, because it is the statistic people most reliably misjudge. In a hundred fair flips, a run of six or seven identical results is the expected outcome, not a sign of anything. Seeing it happen with a coin you know is fair is a far better argument than being told the maths — there is a longer piece on exactly this.
The flip is genuinely fair
Each flip draws from the browser's cryptographic random source, and the result is an exactly even split between the two faces with no bias towards either. A real coin is not quite this fair — the physics of a flipped coin very slightly favours the face it started on — so this is, oddly, more even than the thing it simulates.
Flips within a batch are independent. The hundredth flip does not know or care what the first ninety-nine did, which is precisely why long runs happen and why they mean nothing.
What a coin is actually good for
A coin toss is the right tool when two options are genuinely close in value, because the cost of deliberating exceeds the difference between them. It is the wrong tool when they are not, and no amount of ceremony changes that.
The best-known use is the one nobody admits to: flipping to find out what you were hoping for. If the result lands and you feel relief or disappointment, you have learned something you could not reach by weighing it up, and you are free to ignore the coin entirely.
Frequently asked questions
Is the coin flip really 50/50?
Yes. Each flip draws from your browser's crypto.getRandomValues, so heads and tails are exactly equally likely — unlike a physical coin, which can be slightly biased by how it's tossed.
How many coins can I flip in one batch?
Up to 100. Batch results show every flip as a colored chip, a heads/tails tally, and the longest streak, and each flip is numbered in the CSV export.
What counts as the longest streak?
The most consecutive flips landing on the same face within your batch. Flipping 100 coins usually produces a surprisingly long streak, which makes it a good intuition-builder about randomness.
How can teachers use the batch mode?
Flip 100 coins to demonstrate the law of large numbers: the tally trends toward 50/50 while individual runs stay streaky. Students can copy each batch's results to compare them.
Do I need this if the site has a dice roller?
A coin is just a two-outcome draw, so this tool is faster for yes/no calls. For three or more outcomes, the dice roller or number generator fits better.
Related randomizers
Further reading
- Best of three: when a single coin flip feels too harsh
One flip decides in half a second, but sometimes a binary call feels too abrupt to accept. Here's why flipping an odd batch and taking the majority changes nothing about the odds — and everything about how the loser feels about it.
- Why a long streak in 100 coin flips doesn't mean it's rigged
Flip a batch of 100 coins and you'll almost always see a streak of five or more somewhere in the run. That's not a broken randomizer — it's exactly what real randomness looks like. Here's the math behind streak length, and why 'it's due' is the wrong instinct.
- Two Choices, One Flip: When a Coin Beats a Wheel
Not every random decision needs a spinning wheel or a weighted list. When a call really is binary, a coin flip is the faster, fairer tool — here's how to tell the difference.