Calculator · Windows 10 and 11
Flip a coin
Press Flip, or click the coin, and it is tossed and lands heads or tails. Every flip goes into a tally with percentages, the current streak and the last flips in order. Need many at once? Flip up to 10,000 coins in one go. Each result comes from your computer's cryptographic random source, so every flip is a true 50:50.
How to flip a coin in Octoolo
- 1
Open Flip a coin
In Octoolo's Calculator, choose Flip a coin, the first tool in the Chance group. Typing coin in the home screen's search finds it too.
- 2
Flip
Press Flip or click the coin. It spins in the air for about a second and lands showing Heads (lime, with an H) or Tails (black, with a T).
- 3
Flip many at once
Type a number under Flip several at once and press Flip with that number, for example Flip 10. The result reads like “6 heads, 4 tails”.
- 4
Read the tally
The tiles count Heads and Tails with their share, the Flips so far and how many of the same side came In a row. Last flips lists them, newest first; Copy takes the list and Start over clears it.
A fair flip: where the result comes from
Each flip takes a random number from Windows' cryptographic random source (the same one used to make encryption keys, reached through crypto.getRandomValues) and keeps one bit of it: heads or tails, each with a chance of exactly one half. The animation is chosen after the result, so how long the coin seems to spin has nothing to do with how it lands.
Real coins are slightly less fair than that. A 2023 study that recorded 350,757 flips by hand found coins landed on the side they started on about 50.8% of the time, because a tossed coin wobbles. A digital coin has no starting side and no thumb, which makes it handy for settling who goes first.
If Windows is set to show less animation (Settings, Accessibility, Visual effects), the coin skips the toss and simply shows the result.
Streaks are normal
A coin has no memory. After five heads in a row, the next flip is still 50:50; the feeling that tails is “due” is known as the gambler's fallacy. What surprises people is how often streaks happen:
- Five of the same side in a row, starting from any given flip, has a chance of 1 in 16 (the first flip can be either side).
- In 20 flips, a run of 5 or more of one side happens about 46% of the time.
- In 100 flips, a run of 6 or more happens about 81% of the time, and a run of 7 or more about 54%.
The In a row tile shows the current streak, so you can watch this happen. Over many flips the share settles near half: with 10,000 coins, heads lands between 49% and 51% about 95 times in 100.
Ways to use it
- Settling a choice between two. Who serves first, which film, which way to go. Decide which side means what before you flip.
- Teaching probability. Flip 10, then 100, then 10,000 coins and watch the percentages tighten towards 50%.
- Best of three or five. Flip one at a time and read the tally; Start over between matches.
For more than two outcomes, roll a die with the dice roller, draw a number with the random number generator, or put the choices on the wheel of names, which also has a Yes or no wheel.
Questions, answered
Is it really 50:50?
Yes. Each flip uses one bit from your computer's cryptographic random source, so heads and tails are exactly as likely as each other.
Can I flip more than one coin?
Yes, up to 10,000 at once with Flip several at once. They are counted in the tally and listed in Last flips.
Does the animation decide the result?
No. The result is drawn first and the coin is turned to land on it.
Is my tally saved?
It lasts while you use the tool. Leave it, or press Start over, and it starts again.
Does it work without the internet?
Yes. It runs in Octoolo on your PC and needs no connection.
Can I turn the animation off?
It follows Windows: with Animation effects switched off in Accessibility settings, the coin lands without being tossed.
Flip a coin, and 16 more apps.
Download for Windows7 days free, then from $3.99 a month for all 17 apps. Windows 10 and 11.