Dice Roller
Roll dice for games and simulations
Dice Roller tool
Standard Dice
Custom Dice
Selected Dice
Dice Roller: key facts
- What it does
- Roll dice for games and simulations
- Category
- Other Calculators
- Cost
- Free, with no account, sign-up, or install.
- Your data
- Runs entirely in your browser — the files and text you enter are never uploaded to a server.
- Last reviewed
- . Report an incorrect result.
What the Dice Roller does
Lost your dice, or need a fistful of them for a tabletop game? This dice roller covers the standard polyhedral set — D4, D6, D8, D10, D12, and D20 — plus any custom-sided die you define, and rolls them with cryptographically secure randomness so every result is fair.
Tabletop and role-playing gamers use it to roll attack and damage dice, board gamers use it when the physical dice go missing, and teachers use it for classroom games. You can stack multiple dice of different types, roll them all at once, and see each individual result alongside the totals.
Using the Dice Roller, step by step
- Tap the standard dice (D4 through D20) to add them, or define a custom die by sides and count.
- Adjust the count for any die in your selection.
- Click "roll dice" to roll everything at once.
- Read each die's individual results and per-type sum, plus the grand total; recent rolls are kept in history.
Standard dice and arbitrary polyhedra
Each die is an independent draw over its faces, and the tool supports the standard tabletop set — four, six, eight, ten, twelve, and twenty sides — plus a custom option for any number of faces and any quantity. Individual results are shown alongside the total, which matters in games where each die is read separately rather than summed.
Every face is equally likely and every roll is independent of the last. A die that has just produced three sixes is no more or less likely to produce another, which is the same point that underlies the gambler's fallacy.
The custom mode is there for the cases physical dice cannot cover: a hundred-sided roll, or a quantity that would be impractical to throw and add by hand.
- A single six-sided die gives each of 1 through 6 a probability of one in six.
- Two six-sided dice give totals from 2 to 12, but not with equal likelihood — 7 arises six ways and 12 only one, so 7 is six times as common.
- Three six-sided dice, the common ability-score roll, average 10.5 with results clustering firmly in the middle.
What makes this one worth using
- It uses cryptographically secure randomness (crypto.getRandomValues), so rolls are genuinely fair rather than subtly biased.
- It supports the full standard polyhedral set plus custom-sided dice, and lets you roll many at once.
- It shows every individual roll and the sums, with a history of recent rolls for reference.
- Rolls happen instantly in your browser, with nothing to sign up for.
Why totals cluster, and what physical dice add
A single die is uniform — every face equally likely — but the sum of several is not. Middle totals can be reached in many more combinations than extremes, so the distribution becomes a peak rather than a flat line, and it approaches a bell shape as dice are added. This is why game systems that roll multiple dice produce reliable, predictable results while single-die systems feel wildly swingy, and it is a practical illustration of the central limit theorem.
The generator here uses the browser's pseudorandom source, which is uniform and independent for these purposes but not cryptographically unpredictable. That is fine for games and unsuitable for anything where a participant has an incentive to predict the outcome — an online gambling system needs a verifiably fair source and usually a published seed commitment.
Physical dice are not perfectly fair either. Cheap injection-moulded dice have hollowed pips that shift the centre of mass slightly, and rounded or chipped edges bias results measurably; casino dice are made with flush pips and sharp edges specifically to avoid this. Whether a digital roll is acceptable at the table is a social question rather than a mathematical one.
Frequently Asked Questions
What do D6, D20, and similar notations mean?
The D stands for "die" and the number is how many sides it has — a D6 is a standard six-sided cube, a D20 is the twenty-sided die common in role-playing games. You can add any of these or define a custom number of sides.
Can I roll several dice at the same time?
Yes. Add as many dice as you need, of mixed types, set the count for each, and roll them together. The results show each die's individual values, the sum per die type, and the overall total.
Are the rolls fair?
They are generated with your browser's cryptographically secure random source, giving each face an equal chance — fairer than many simple random functions and free from the slight imbalances a physical die can have.
Can I create a die with an unusual number of sides?
Yes. Beyond the standard set, the custom-dice option lets you define any number of sides — a D100 for percentile rolls, or a D3, D7, or whatever a game calls for — and roll any quantity of them alongside the standard dice.
