Free Coin Flip Online
Free Coin Flip Online streaks, batch 10 000 flips, and optional crypto-grade RNG. Full history, CSV download, free, client-side.
Fair heads-or-tails with a clickable coin, streak tracking, 10 000-flip batches, and a real crypto-grade RNG option — all running in your browser.
Counters
Streaks
Recent flips (last 50, newest first)
How to Use Free Coin Flip Online
- Click the coin or the Flip button - or just hit
Space. The coin animates briefly, then reveals H or T. - Read the counters: heads, tails, total, heads %, tails %, and deviation from a perfect 50/50 split. All update on every flip.
- Track streaks: the current streak (e.g. "3 × Heads"), the longest heads streak, and the longest tails streak recorded since the last reset.
- Batch flip up to 10 000 flips at once with a count input and the "Flip N times" button. The result folds into the running counters.
- Pick an RNG:
crypto.getRandomValues(default; cryptographically strong) orMath.random(fast but not cryptographically secure). The badge shows which one is actually in use. - Scan the last 50 flips below the streaks - newest first, shown as
H → T → H → …. - Reset clears all counters and history. Copy report or Download .txt exports the full history plus a summary.
Frequently asked questions
Is the coin flip truly random?
With the default crypto.getRandomValues source, yes – it’s a cryptographically strong PRNG provided by the browser. With the Math.random option the result is a seeded pseudo-random number that is fast but not cryptographically secure. Both give a fair 50/50 split in expectation; neither is biased towards heads or tails.
Is my flip history uploaded anywhere?
No. History lives in memory while the page is open. It never touches a server and is cleared when you press Reset or refresh the page.
What’s the difference between crypto.getRandomValues and Math.random?
Math.random is a deterministic PRNG (typically xorshift128+) whose state is known to JavaScript and therefore predictable. crypto.getRandomValues reads from the browser’s CSPRNG, which is unpredictable even if an attacker sees every past output. For casual flips either is fine; for anything security-sensitive, pick the crypto option.
Can I use this for important decisions?
The randomness is genuine – but a coin flip is only ever fair if you are honestly willing to accept either outcome. Use it to break ties where both options work, not to resolve decisions you actually have a preference on.
Why would I use an online coin flip?
Convenience when you don’t have a coin, running many flips quickly for probability demos, auditable history when teaching, and the confidence of a fair RNG rather than a physically-biased coin.
How many flips can I run at once?
Up to 10,000 in a single batch. The cap keeps the tab responsive. For teaching the law of large numbers, ten thousand flips is already enough to see the distribution settle near 50/50.
Are real coins biased?
Not meaningfully. Academic studies find real coin flips are very close to 50/50 – the small bias they do find is due to the flip itself, not coin weight. This tool is not “fairer than a real coin”; it is fair in a different way (software RNG vs physical mechanics).
Why does my batch of 100 show 43-57 heads?
That’s expected variance. For 100 flips the 95% confidence interval is roughly 40-60. A run of 10,000 usually lands between 4,900 and 5,100. Watch the “Deviation from 50/50” counter shrink as totals grow – that is the law of large numbers in action.
Can I reset the statistics?
Yes – click the Reset button. It clears both counters and history in one step. (Refreshing the page also works and is equivalent.)
Does it work offline?
After the page loads, yes. HTML, CSS, and JS are self-contained – disconnect Wi-Fi and keep flipping.