Coin Flip
Flip a virtual coin one or more times and see instant results with head/tail statistics.
Heads ratio over time
How It Works
The Coin Flip generates fair head/tail outcomes using cryptographically secure randomness from your browser’s crypto.getRandomValues — the same source used for TLS keys and password generation. Each flip pulls one random bit and maps it to heads or tails, giving a true 50/50 probability that no streak or seed can bias. Flip a single coin for a quick decision, or set the count higher (up to several thousand) and the tool runs every flip and reports the breakdown — useful for visualising probability convergence: 10 flips can easily land 7-3, but 1,000 will sit very close to 500-500. The result of each flip is shown alongside a running total of heads and tails counts, so you can confirm fairness empirically. There is no animation, no fake delay, no analytics tracking — just an instant honest answer, ready when you need a tie-breaker. Flipping runs entirely in your browser, the result exists only in the page, and the random source is genuinely unbiased.
Worked Example
Flip 100 coins at once: expect a result near 50/50, but rarely exactly — the tally cards show the split and the chart tracks it over repeated batches. Watch for streaks: runs of six or more identical results appear far more often than intuition suggests, which is precisely why humans are bad at faking random sequences (real randomness is streakier than people allow). For settling a single decision, one flip with the satisfying animation does the job — cryptographically fair, with no way for either side to claim the toss was rigged.
Use Cases
- Making a fair binary decision between two options
- Settling a tie-breaker in a game
- Teaching probability with a large number of flips
- Running a quick random yes/no decision
Frequently Asked Questions
- Is the coin really fair?
- Yes — bits come from crypto.getRandomValues, which is backed by the OS secure random source. Each flip is statistically independent and equally likely to be heads or tails.
- Why did I get six tails in a row?
- Streaks happen — over many flips, runs of equal results appear about as often as a fair coin would predict. Try 1,000 flips and you will see the totals converge to roughly 500-500.
- Can I bias the result?
- No — there is no input that affects the outcome. Each flip is independent.
- Is my result logged anywhere?
- No. Flips happen in your browser and the outcome exists only in the current page.
- Why use this instead of Math.random?
- Math.random is a non-cryptographic PRNG that some environments seed predictably. crypto.getRandomValues is cryptographically secure and unbiased, which is the right choice when fairness matters.