Coin Flip
Flip a fair coin, name the two sides, and keep a running tally.
Ready
Tap flip to settle it
Options
How many flips at once
Deciding between two things? Name the sides and the result reads back in your own words.
This flips a fair coin using your browser's cryptographic random generator. Flip once to settle something, or up to 100 times at once.
You can rename the two sides so the result reads as your actual choice rather than heads or tails, and it returns the running tally and the longest streak across a batch.
What is a coin flip?
A coin flip is the simplest fair choice there is: two outcomes, each with a 50% chance, and no way to influence which one you get.
That is exactly why it settles arguments. Nobody picked the answer, so nobody can complain about it. The fairness comes from the fact that neither side has an advantage, not from anything about the coin itself.
This flipper uses your browser's cryptographic random generator, so each flip is genuinely independent. You can also rename the two sides, which turns it from heads-or-tails into a straight answer to whatever you are actually deciding.
What to enter
- How many flips at once
- Flip once for a decision, or up to 100 at a time to watch the heads and tails tally even out.
- Heads means
- Rename this side to your first option, like 'Pizza'. The result then reads as an answer rather than a side of a coin.
- Tails means
- The second option. Leave both blank to keep plain heads and tails.
Where a coin flip is genuinely used
- Sport
- The toss decides who kicks off, who bats, or which end a team defends. It is used precisely because neither side can claim an unfair edge.
- Tied elections
- Several US states break a tied local race by drawing lots, which has included a coin toss. Rare, but it has genuinely decided seats.
- Everyday decisions
- Where to eat, who does the washing up, who goes first. Small choices where the cost of arguing exceeds the cost of being wrong.
- Teaching probability
- The standard first example, because the odds are obvious but the results are surprisingly streaky.
- Finding out what you want
- Flip, then notice your reaction. Feeling disappointed by the result tells you which option you were quietly hoping for.
What this assumes
The coin is perfectly fair, so heads and tails are exactly 50/50.
Each flip is independent. Nothing about previous flips changes the next one.
How to calculate coin flip odds
Every flip is 50/50. Working out a run of flips is just multiplication, because each one has to go your way.
- 1/2
- The chance of heads on any single flip
- n
- How many flips in a row
One flip. Two possible results, one of them heads. That is 1 in 2, or 50%.
Two flips. Four possible results: HH, HT, TH, TT. Only one is two heads, so 1 in 4.
Keep doubling. Each extra flip doubles the number of possible sequences. Three flips gives 8, four gives 16, ten gives 1,024. For anything more involved, use the probability calculator.
See a worked example: the odds of ten heads in a row
- Flips
- 10, all heads
Each flip is a 1 in 2 chance, and all ten have to land heads.
So multiply: 2 x 2 x 2 ... ten times over, which is 2¹⁰.
2¹⁰ = 1,024.
Worth noting the flip side: getting exactly 5 heads out of 10 only happens about 24.6% of the time. An even split is the single most likely result, but it is still the exception.
1 in 1,024, or about 0.1%
Frequently asked questions
This flipper is, because the result comes from a random number generator with no bias either way.
A real physical coin is very slightly less perfect. Research has found a small bias towards the side that was facing up when it was flipped, because the coin wobbles as it spins. The effect is tiny, roughly 51/49, and it disappears if you catch and flip it onto the back of your hand.
No. Six in a row happens about once in every 64 attempts, so across a few dozen flips it is entirely ordinary.
Streaks feel wrong because people expect random results to alternate neatly. Genuinely random sequences clump far more than most of us intuitively expect.
No. The next flip is still exactly 50/50. The coin has no memory of what it did before.
This is the gambler's fallacy, and it is the single most common mistake people make about probability. What is true is that a long run of heads was unlikely to happen *in advance*; once it has happened, it changes nothing about what comes next.
Far more than people expect. In 10 flips, anything from 3 to 7 heads is perfectly normal, so a 7-3 split proves nothing at all.
You need hundreds of flips before a small bias becomes visible above the noise. Set the flip count to 100 and run it a few times to see how much the ratio still moves around.
For small ones, yes, and it is quicker than arguing. For anything that matters, use it differently: flip it, then pay attention to how you feel about the answer before you act on it.
If you are relieved, go with it. If you immediately want best of three, you already knew what you wanted and the coin has just told you.
Problems people actually run into
Expecting an even split in a small number of flips
People flip ten times, get 7 heads, and conclude something is wrong. Nothing is: that result comes up roughly one time in six.
Even splits are the most likely single outcome but still a minority. Exactly 5 heads in 10 flips happens only about a quarter of the time, so three quarters of all runs are uneven. The ratio only settles down over hundreds of flips, not a handful.
Results are estimates for general information only and are not professional financial, medical, or legal advice. Read our full disclaimer.
Last updated: August 29, 2026