Coin Flip & Dice Roller
Flip a coin or roll dice for quick decisions
Last updated
How to Use This Tool
Click to flip a coin and get a random heads/tails result instantly.
When Should You Use This Tool?
Use this when you need a quick 50/50 decision without a physical coin.
See also: Unit Converter, Percentage Calculator .
How do I flip a coin online?
Leave Action set to Flip Coin and press Go! The result, Heads or Tails, appears straight away. Press Go! again for another flip. Each flip is independent, so earlier results have no effect on the next one.
To roll dice instead, switch Action to Roll Dice, choose the number of sides (4, 6, 8, 10, 12 or 20) and how many dice to roll, from 1 to 10. If you type a number outside that range, such as 0, a negative number or 25, the tool rolls the nearest allowed amount (1 or 10) and updates the box to match. When you roll more than one die, the tool lists each die and adds up the total for you, for example "4, 2, 6 (Total: 12)".
Is a coin flip really 50/50?
Yes, in this tool every flip has exactly the same chance of heads as tails. It draws a random number between 0 and 1 using your browser's Math.random() function and calls it Heads if the number is below 0.5 and Tails otherwise, so the two halves are equal. There is no thumb, no air resistance and no way to catch the coin, which are the things that can nudge a real toss slightly off balance.
A fair coin does not mean perfectly even results in a short run. Flip 10 times and getting 6 heads and 4 tails, or even 7 and 3, is completely normal. The split only settles close to 50/50 over hundreds of flips.
What are the chances of getting heads several times in a row?
The chance of a specific streak is one half multiplied by itself once per flip. Two heads in a row is 1 in 4, three is 1 in 8, and each extra flip halves the odds again.
| Heads in a row | Odds | Probability |
|---|---|---|
| 2 | 1 in 4 | 25% |
| 3 | 1 in 8 | 12.5% |
| 4 | 1 in 16 | 6.25% |
| 5 | 1 in 32 | 3.13% |
| 7 | 1 in 128 | 0.78% |
| 10 | 1 in 1,024 | 0.098% |
Those odds are for a streak starting on a particular flip. Over a long session, streaks are much more likely than most people guess. In 100 flips, the chance of seeing at least one run of 5 or more heads is about 81%, and a run of 5 or more of the same side (heads or tails) is about 97%. So if you flip a lot and see a long streak, it is not a sign that something is broken.
Does a streak make the other side "due"?
No. After five heads in a row, the next flip is still exactly 50/50. Believing that tails is now more likely is known as the gambler's fallacy. The coin, virtual or real, has no memory of what came before.
How do I make a fair decision with a coin flip?
- Agree which option is Heads and which is Tails before anyone presses the button.
- Agree that one flip decides it. "Best of three" is fine too, but settle that beforehand.
- Press Go! once and accept the result.
A useful side effect: if you feel disappointed by the result, that tells you which option you really wanted.
For more than two options, use dice. A d4 covers four choices, a d6 six, and so on. If you have three options, roll a d6 and let 1 to 2, 3 to 4 and 5 to 6 stand for each one.
What are the odds for each type of die?
Every face of a fair die has an equal chance, so the probability of any single number is 1 divided by the number of sides. The average roll is the number of sides plus one, divided by two.
| Die | Chance of any one face | Average roll | Common use |
|---|---|---|---|
| d4 | 25% | 2.5 | Tabletop RPG damage rolls |
| d6 | 16.7% | 3.5 | Board games, Yahtzee style games |
| d8 | 12.5% | 4.5 | RPG weapon damage |
| d10 | 10% | 5.5 | Percentile rolls (use two), choosing 1 to 10 |
| d12 | 8.3% | 6.5 | RPG damage, picking a month |
| d20 | 5% | 10.5 | Attack rolls and checks in games like Dungeons and Dragons |
Rolling several dice changes the picture. With two six sided dice, the totals from 2 to 12 are not equally likely: 7 comes up most often (6 of the 36 combinations, about 16.7%), while 2 and 12 each need one exact combination (1 in 36, about 2.8%). That is why so many board games treat 7 as special.
Good uses for a virtual coin and dice
- Settling small disputes: who picks the film, who goes first, who pays for coffee.
- Game nights without the box: roll the right die for a board game or RPG when the physical dice are missing.
- Teaching probability: have a class flip 50 times and compare the tally with 50/50, or roll two dice and chart the totals.
- Sports and team starts: decide kick off or first serve when no coin is at hand.