Online Tool Store
Coin Flip
Flip a virtual coin with an even 50/50 chance, then track every result — heads and tails totals, your current run, and your longest streak. Runs in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
One flip already made so you can see the result — flip again for your own.
- Heads
- Tails
- Current run
- Longest run
History
How it works
- Press "Flip the coin". The coin spins and lands on the side that was actually drawn.
- Every result is added to the history, newest first, and the totals above it update — heads, tails, your current run of the same side, and the longest run of the session.
- Press "Reset history" whenever you want a clean slate; it clears the totals and starts a fresh run with a new flip.
Where the 50/50 comes from
Each flip asks your browser's cryptographic random number generator for one byte, then reads only its last bit:
byte = crypto.getRandomValues(new Uint8Array(1))[0] → heads if (byte & 1) === 0, else tails
A byte is uniform over its 256 possible values, and 256 splits exactly in half — 128 even, 128 odd — so each side
has probability exactly 1/2 with no rounding left over. That last part is why this isn't done with
Math.random(): scaling a floating-point number into a range can leave one outcome very slightly more
likely, and Math.random() makes no fairness guarantee in the first place.
Flips are also independent, which is the part people find surprising. The chance of any specific run of 5 heads is 1/2⁵ = 1/32, so in a hundred flips a run that long is unremarkable rather than evidence of a broken coin.
FAQ
Is the flip actually fair, or does it favour one side?
It's an even 50/50. Each flip takes one random byte from your browser's crypto random number generator and reads its last bit — because a byte has 256 equally likely values and 256 divides exactly in two, heads and tails come up with identical probability. There's no hidden weighting and no house edge.
Can I predict or influence the next result?
No. Every flip is drawn independently at the moment you click, so the coin has no memory of what came before — a run of six heads doesn't make tails any more likely on the seventh. That's the gambler's fallacy, and the streak counter exists to show you how ordinary long runs really are.
What counts as a streak here?
"Current run" is how many times the same side has come up in a row, counting back from your most recent flip. "Longest run" is the best such run in your whole session. Both show a dash until you actually have a run of two or more.
Is my flip history saved anywhere?
No. The history lives only in this page's memory, so nothing is uploaded, stored on our side, or kept in your browser between visits. Refreshing the page or hitting "Reset history" starts a clean session.
Why does a new flip appear the moment the page loads?
So you can see a real result straight away rather than an empty panel. That first flip is a genuine one, drawn the same way as every other, and it counts in the totals — hit "Reset history" if you'd rather start your own run from scratch.
Can I flip several coins at once?
Not in one click — it's one flip per press, which keeps the history and the streak counters meaningful. For a large sample, keep clicking and watch the heads percentage settle towards 50%.
How we compare
| Feature | Online Tool Store | Typical ad-supported coin flip sites | An actual coin |
|---|---|---|---|
| Running history of every flip | ✓ | Varies — many show only the latest result | ✗ |
| Streak counters, current and longest | ✓ | ✗ | Only if you write them down |
| Provably even 50/50, no physical bias | ✓ | Usually, but the method is rarely stated | Close, though catch and spin can skew it |
| No ads or pop-ups on the page | ✓ | ✗ | ✓ |
| Nothing about your flips leaves the page | ✓ | Varies — many log results server-side | ✓ |
| Nothing to carry — works with empty pockets | ✓ | ✓ | ✗ |
For settling who goes first, splitting a chore, or picking between two options, any coin will do — the reason to use this one is the record it keeps. The history and streak counters turn a one-off decision into something you can review, and they make it obvious how normal a long run of one side really is.