Flip a Coin
Use this coin flip tool for a fair heads-or-tails call. Each toss is an even 50/50 draw from a secure random source, and the running tally keeps score so you can watch the split even out over many flips. Assign your two options, flip, and accept the verdict.
Flip a Coin tool
How to use it
- Click Flip the coin.
- Watch it spin and land on heads or tails.
- Keep flipping; the tally tracks how the results split.
What is a coin flip?
A coin flip, or coin toss, is the simplest fair random draw there is: two outcomes, heads or tails, each with a probability of exactly one half. This virtual version decides each coin flip with crypto.getRandomValues, the browser’s secure random source, so the odds are a true 50/50 and no result is influenced by the last one. Streaks follow a single rule:
P(same side n times in a row) = (1/2)^n
5 heads in a row = 1/32 ≈ 3.1%That is why a coin flip settles arguments so well. Nobody can predict it, nobody can steer it, and nobody can claim the next result is due.
Worked example
Odds of a streak
| Run of heads | Probability | Roughly |
|---|---|---|
| 2 in a row | 1/4 | 25% |
| 3 in a row | 1/8 | 12.5% |
| 4 in a row | 1/16 | 6.25% |
| 5 in a row | 1/32 | 3.1% |
| 7 in a row | 1/128 | 0.8% |
| 10 in a row | 1/1024 | 0.1% |
A fair 50/50, every time
Each flip is an independent draw from crypto.getRandomValues, the browser's secure random source, so heads and tails are exactly equally likely and past results have no effect on the next one. A well-made physical coin has the same property, which is why flipping is the classic way to settle a choice between two options. Nobody can argue with it, and it takes two seconds. Nothing about the animation affects the result; the outcome is decided before the coin starts to spin.
Streaks are normal
Over a handful of flips you will often see lopsided runs, like five heads in a row, and that is expected. The chance of any particular five-flip run is 1 in 32, so across a few dozen flips a streak like that shows up sooner or later. Each flip is still 50/50. The tally makes the long-run pattern visible: as the total climbs, the heads percentage drifts toward 50, an everyday demonstration of the law of large numbers. Flip ten times and you might see 70 percent heads. Flip a hundred and it is usually within a few points of 50.
Ways to use it
Assign one option to heads and the other to tails before you flip, and agree to accept the result. That works for who goes first in a game, which restaurant to pick or which of two chores to do now. For a fairer contest, play best of three. Teachers use the tally to introduce probability: have students predict the split, run 50 flips as a class and compare. The count is kept only for the current visit. Reload the page or click Reset to start at zero. Nothing is stored or sent anywhere.
Common uses
- Settling a yes-or-no or either-or decision
- Deciding who goes first in a game or sport
- Demonstrating probability and 50/50 odds in class
- Breaking a tie fairly
- Best-of-three or best-of-five showdowns
When to use it
- Two options and no preference: a coin flip for decision making ends the debate in two seconds.
- You need to flip a coin online because nobody at the table carries change anymore.
- Deciding who kicks off, serves first or gets first pick in a draft.
- A math class wants to flip a coin 100 times and watch the heads percentage settle near 50.
- A best-of-three coin toss makes a small stake feel fair to both sides.
Related tools
Dice Roller covers decisions with more than two outcomes, from a d4 to a d100.
Wheel of Names picks among named options, like restaurants or students, instead of heads and tails.
Random Number Generator draws from any number range when two sides are not enough.