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Dice Roller

Free online dice roller — roll d4 to d100, multiple dice, and a modifier for board games and tabletop RPGs, with the total and average.

Number of dice

Sides per die

Modifier (±)

Total

Dice sum

4.5

Average per die

Fair, cryptographically random rolls for board games, tabletop RPGs (D&D), and classroom use. Supports d4 to d100, up to 50 dice, plus a modifier.

Instant insight

2 dice totalling 9
Adding dice changes the shape, not just the range. With 2 dice the totals cluster in the middle: there are many ways to make a middling total and only one way to make the maximum.
The more dice you add, the tighter that clustering gets — the central limit theorem showing up on a tabletop.
Dice have no memory
After five sixes, the next roll is still one in six. The gambler's fallacy is believing a run must correct itself.
What does happen is regression to the mean: unusual runs get diluted by later rolls, not cancelled by them.

Worked out in your browser — nothing is sent anywhere.

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Everyday Uses

Tabletop gaming

Roll any combination of dice with modifiers when you don't have a set to hand.

Making a random choice

Settle a decision fairly without arguing over who picks.

Seeing distributions

Roll repeatedly to watch how summed dice cluster toward the middle.

Teaching probability

Demonstrate independence and streaks with a large number of quick trials.

Why two dice are not flat

2d6 peaks at seven because six combinations make it and only one makes two. Roll a few hundred and the triangle appears — the clearest demonstration of why sums of random values bunch in the middle.

Advantage, disadvantage and rerolls

Rolling twice and taking the higher shifts the odds considerably more than most players expect. Simulating it beats arguing about it at the table.

Frequently Asked Questions

Are these dice genuinely random?

They use the browser's cryptographically secure random number generator via the Web Crypto API, not the weaker Math.random. Each roll is independent and uniformly distributed across the faces, with no seed you could predict and no history influencing the next result. For gaming purposes that is as fair as a physical die, and arguably fairer — real dice have manufacturing imperfections and wear.

What does dice notation like 3d6+2 mean?

The number before the d is how many dice, the number after is how many faces, and any modifier is added to the total. So 3d6+2 means roll three six-sided dice, add them, then add two — giving a range of 5 to 20. Notation like 1d20 is a single twenty-sided die, standard in tabletop role-playing. 2d10 and 1d20 both span 2–20 and 1–20 but have completely different probability shapes.

Why is rolling 2d6 not evenly distributed?

Because multiple combinations produce the same total. There is only one way to roll 2 (1+1) but six ways to roll 7, so 7 comes up six times as often. Totals from summed dice follow a bell-shaped distribution, which is why board games using 2d6 have such different feel from those using a single d12 across the same range. One die is flat; two or more are peaked.

Is a physical die ever biased?

Slightly, yes. Standard consumer dice have hollowed pips that remove a tiny amount of material, making the six face marginally lighter and the one face marginally more likely to land down — so six comes up very slightly more often. Casino dice use flush, filled pips and tighter tolerances precisely to eliminate this. The effect is far too small to notice in casual play but is real and measurable over many thousands of rolls.

Does a run of the same number mean anything?

No — and expecting otherwise is the gambler's fallacy. Dice have no memory, so after four sixes the next roll is still one in six. Runs are also far more common than intuition suggests: in 100 rolls of a d6, a streak of three identical results is more likely than not. Genuinely random sequences look clumpier than people expect, which is why hand-made fake data usually looks too evenly spread.

Can I use this instead of physical dice for a game?

For casual and remote play, yes — it is fair and convenient. Two practical caveats: some groups prefer physical dice for the social ritual, and organised tournament play often requires physical dice witnessed by opponents. For anything with stakes, agree the method with everyone beforehand.