About the Flip a Coin
Flip a fair virtual coin to settle a decision, start a game or pick who goes first. Tap Flip for one toss, or flip 10 or 100 at once, and the page keeps a running tally of heads, tails and the longest streak.
Each result comes from your browser's cryptographic random number generator, the same kind used for passwords and security keys.
How it works
The browser produces a random 32-bit number with crypto.getRandomValues. Even numbers are heads and odd numbers are tails; because half of all 32-bit numbers are even, both sides have exactly the same chance.
Flips are independent: the coin has no memory, so after five heads in a row the next flip is still exactly 50/50. Long streaks feel suspicious but are normal, as the table below shows.
P(heads) = P(tails) = 1/2 on every flip P(a given sequence of n flips) = (1/2)^n
Assumptions and limits
- A real coin isn't perfectly fair: studies of real tosses have found a slight bias towards the side that started facing up. This virtual coin has no such bias.
- The tally lives only on this page; reloading clears it.
Worked examples
Settling a choice
Call heads or tails before tapping Flip. One flip is enough: the result is 50/50 whichever side you called.
Checking fairness yourself
Flip 100 times a few rounds. Heads usually lands between about 40 and 60 per hundred; exactly 50 is less common than you might expect, happening about 8% of the time.
A streak of five
In 20 flips there is about a 46% chance of seeing five or more of the same side in a row, so a streak like that is close to a coin toss itself.
Chance of at least one streak of the same side
Exact values for heads or tails runs, rounded to one decimal place; computed by counting every possible sequence.
| Flips | 3 in a row | 4 in a row | 5 in a row | 6 in a row | 7 in a row |
|---|---|---|---|---|---|
| 10 | 82.6% | 46.5% | 21.7% | 9.4% | 3.9% |
| 20 | 97.9% | 76.8% | 45.8% | 23.7% | 11.5% |
| 50 | over 99.9% | 98.1% | 82.1% | 54.4% | 30.9% |
| 100 | over 99.9% | over 99.9% | 97.2% | 80.7% | 54.2% |
How to use the Flip a Coin
- Call it. Decide which side wins before you flip.
- Flip. Tap Flip, or flip 10 or 100 times for a quick experiment.
- Read the tally. Heads, tails, percentages and streaks update after every flip.
Frequently asked questions
Is this coin flip really 50/50?
Yes. Each flip takes one random number from your browser's cryptographic generator, and exactly half of the possible numbers mean heads. Nothing about earlier flips, the time or your device changes the odds.
Why did I get heads five times in a row?
Streaks are more common than they feel. In 20 flips the chance of five or more of the same side in a row is about 46%, and in 100 flips it is about 97%. A streak doesn't mean the coin is broken.
After several tails, is heads due?
No. This is the gambler's fallacy: a fair coin has no memory, so the next flip is 50/50 no matter what came before. Over many flips the proportions even out because of new flips, not because the coin corrects itself.
Can someone predict or rig the result?
Not from this page. The random numbers come from your own device's secure generator, nothing is sent to a server, and the code doesn't favour either side. You can verify the tally over hundreds of flips.
Is a real coin toss fairer?
Not quite. Large experiments with real coins have measured a small same-side bias, around 51% for the side facing up at the start. A virtual coin avoids physical effects like that.
Sources
This tool runs entirely in your browser. What you enter or upload stays on your device and is never sent to our servers.