Roll a Dice
Roll a dice online instantly with this free dice roller. Roll a single d6 or up to 100 virtual dice at once — d4, d6, d8, d10, d12, d20, d100 or your own custom die — and see the total, a modifier, advantage and your stats straight away. Every random dice roll runs securely in your browser, so it works as an online dice roller for board games, tabletop RPGs and classroom probability.
Part of Randomfella’s free random tools. See every tool and guide on the home page.
Dice probability explained
How a Random Dice Roll Works
A fair die gives every face the same chance. On a d6 each number from 1 to 6 comes up one time in six, and on a d20 each face comes up one time in twenty. Every roll is independent, so earlier rolls never change what comes next.
Rolling a Single Die: d6 Roll to d20 Roll
A d6 roll has six equally likely results and an average of 3.5. A d20 roll has twenty and an average of 10.5. The more faces a die has, the less likely any one result is: a natural 20 is 1 in 20, while any single face of a d100 is 1 in 100.
Why Real Dice Are Never Quite Perfect
Physical dice can have tiny flaws in balance or shape. A digital roll has none of them: the result comes from your browser’s cryptographic random number generator and every face is exactly equally likely.
Rolling Several Dice at Once
Add dice together and the totals stop being equally likely, even though each die is fair. With two six-sided dice there are 36 equally likely combinations, but only one makes 2 and six make 7.
Why Totals Bunch in the Middle
Middle totals can be made in more ways than extreme ones, so they come up more often:
- 2d6 total of 7: 6 in 36, or 1 in 6
- 2d6 total of 2 or 12: 1 in 36 each
- 3d6 total of 10 or 11: 1 in 8 each
- 3d6 total of 3 or 18: 1 in 216 each
The more dice you roll, the more the totals form a bell-shaped curve around the average. The Stats panel draws this curve for your current pool and compares it with your own rolls.
Modifiers, Keep Highest and Advantage
A modifier shifts every total by the same amount and changes no probabilities. Keeping the highest or lowest dice does change them, because the dropped dice are chosen after the roll.
Keep Highest or Lowest N
Rolling 4d6 and keeping the highest three gives an average of about 12.24, compared with 10.5 for plain 3d6, which is why it is a popular way to generate ability scores.
Advantage and Disadvantage
Advantage rolls two d20 and keeps the higher, lifting the average from 10.5 to about 13.8 and the chance of a natural 20 from 5% to 9.75%. Disadvantage keeps the lower, giving an average of about 7.2 and a 0.25% chance of a natural 20.
Streaks and the Gambler’s Fallacy
Random sequences contain runs. The same face three times in a row on a d6 happens 1 time in 36 rolls, and twice in a row 1 time in 6, so streaks are normal.
Why Streaks Don’t Mean the Dice Are Due
The gambler’s fallacy is the belief that a streak must correct itself. Each roll is independent, so after five sixes the next roll is still a 1 in 6 chance of another six.
Technical Specs: How Randomfella Rolls
Randomfella uses your browser’s built-in cryptographic random number generator, window.crypto.getRandomValues(), for every die.
No Modulo Bias
A naive method that takes a random number modulo the number of faces slightly favours some faces. Randomfella uses rejection sampling instead: values that would cause bias are thrown away and drawn again, so every face has exactly the same probability.
Result First, Then Animation
The roll is decided before the toss animation begins. The animation only shows the result that has already been chosen, and nothing is sent to a server.
Roll a Dice FAQ
Fairness and privacy
Is this online dice roller really fair?
Yes. Every die uses your browser’s secure random number generator (Web Crypto API), with a method that removes modulo bias, so each face is exactly as likely as every other. The result is decided before the animation starts, so the animation can’t influence it.
Does it store or send my rolls anywhere?
Your rolls, settings and awards stay on your device. The page uses anonymous analytics that count how often Roll is pressed and how many dice were used, but never the values you rolled.
Why did I roll the same number three times in a row?
Streaks happen naturally with fair dice. The Streak Towers and Awards tab show how often repeats should appear (the same face three times in a row on a d6 is 1 in 36).
Using the tool
How do I roll dice online?
Press Roll (or Space or Enter). You start with one d6; tap a die chip such as d20 to add dice, and Roll again repeats the same pool.
How many virtual dice can I roll at once?
From 1 to 100 in total, mixed however you like, for example 3 × d6 plus 1 × d20. Up to about 30 are drawn as full dice; more shrink to compact tiles.
What dice can I use, from a d6 roll to a d20 roll?
d4, d6, d8, d10, d12, d20 and d100, plus a custom die with any number of faces from 2 to 1,000.
How do modifiers and keep highest or lowest work?
A modifier adds or subtracts a fixed number from the total. Keep highest or lowest N counts only those dice in a group (for example 4d6 keep highest 3); dropped dice stay visible, dimmed and struck through.
What are advantage and disadvantage?
Advantage rolls two d20 and keeps the higher; disadvantage keeps the lower. Both are one tap, and the history records them as such.
What do the keyboard shortcuts do?
Space or Enter rolls. 1–9 sets the number of dice in the first group, A rolls with advantage, D with disadvantage and C clears the history. You can turn shortcuts off in Appearance.
Advanced features
Can I download my results?
Yes. You can export your history to CSV with timestamps, pool, every die value, modifier and total. The file records what happened on your device.
How do the awards work?
Natural 20s and 1s, repeated faces, all dice matching and the lowest or highest possible totals are tracked and counted. They stay when you press the main Reset; only the Awards tab’s own reset clears them.
Can I use it as virtual dice for board games and tabletop RPGs?
Yes. Mixed pools, modifiers, keep highest or lowest and advantage cover most tabletop rules, and a custom die handles unusual dice.
Does it work in other languages?
Yes — English, Spanish, French and Arabic.
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