This dice roller lets you roll anywhere from one to ten dice at once, in any standard tabletop size — d4, d6, d8, d10, d12, d20, or d100 — with an optional modifier added automatically to the total. It's built for the exact notation used at the table: type "2d6+3" and you'll set 2 dice, choose d6, and enter 3 as the modifier, and the tool shows you each individual die result plus the final sum.
Arb Digital built this dice roller as one of a set of free, genuinely useful browser tools. Whether you're running a Dungeons & Dragons session over video call, teaching a probability lesson, settling a board game dispute, or just curious how many times a d20 actually lands on 20 in a row, this tool gives you a fast, fair answer with no app download and no account.
What This Dice Roller Does
The tool simulates physical dice using your browser's cryptographically secure random number generator, so every face has an equal, unbiased chance of coming up — the same fairness guarantee a physical, well-manufactured die is supposed to offer, without the risk of a chipped edge or an uneven surface skewing results over hundreds of rolls. You choose how many dice to roll, what size they are, and any flat modifier to add, and the dice roller returns both the individual face values and the combined total instantly.
Every roll is logged to a running history so you can review a full session afterward — useful for tracking damage rolls in a long combat encounter, verifying nobody's memory of "I definitely rolled higher" is playing tricks on them, or simply reviewing a sequence of rolls for a probability exercise.
How to Use It
- Set the number of dice. Choose any amount from 1 to 10 in the "Number of dice" field.
- Choose the dice type. Pick from the seven standard tabletop sizes: d4, d6, d8, d10, d12, d20, or d100 (percentile die).
- Add a modifier if needed. Enter a positive number to add to the total, or a negative number to subtract — leave it at 0 if you just want the raw dice sum.
- Click "Roll Dice." Every die's individual result appears as a chip, and the total (including modifier) shows in the result panel.
- Check the distribution panel. It tracks how often each face of the currently selected die type has come up this session, so you can see the actual spread building over many rolls.
- Review the history. Every roll is logged with its full breakdown, so you can scroll back through an entire session.
The Formula / How It's Calculated
For each individual die, the tool generates one random integer from 1 to the number of sides (a d6 produces 1 through 6, a d20 produces 1 through 20, and so on), using crypto.getRandomValues() rather than the more common Math.random(). This matters because crypto.getRandomValues() draws from the browser's cryptographically secure random source — the same category of randomness used to generate encryption keys — rather than a seeded pseudo-random sequence that is, in principle, predictable. For a deeper technical explanation, see the MDN documentation on getRandomValues().
The total shown is simply the sum of every individual die result plus your chosen modifier: Total = (die 1 + die 2 + … + die n) + modifier. For probability background on why rolling multiple dice produces a bell-shaped spread rather than a flat one, Math Is Fun's two-dice probability page is a clear, accessible reference, and for a more formal treatment of discrete probability distributions, Khan Academy's statistics and probability course covers the underlying theory in depth.
Tabletop Gaming: Reading Dice Notation
Tabletop role-playing games and board games use a compact shorthand for describing any roll: NdS+M, where N is the number of dice, S is the number of sides on each, and M is a flat modifier added at the end. "3d6" means roll three six-sided dice and add them together. "1d20+5" means roll one twenty-sided die and add 5 — the classic Dungeons & Dragons attack roll format. This dice roller maps directly onto that notation: the "Number of dice" field is N, the "Dice type" dropdown is S, and the "Modifier" field is M.
Different die sizes serve different purposes across game systems. The d20 is the backbone of most modern tabletop role-playing games for attack rolls, skill checks, and saving throws, because its 20 faces give fine-grained, roughly even odds for pass/fail outcomes. The d6 is the most common general-purpose die, used for everything from classic board games to weapon damage. The d4, d8, d10, d12, and d100 (rolled as two d10s or a single percentile die, depending on the physical set) fill in specific damage dice and percentage-based mechanics. Having all seven in one dice roller means you never need to dig through a dice bag mid-session — or worry about losing a d4 under the couch again.
Probability: What Multiple Dice Actually Tell You
Rolling a single die produces a flat, uniform distribution — every face from 1 to the number of sides is equally likely. Rolling and summing multiple dice changes that completely. Two six-sided dice can't produce a 2 or a 12 in more than one way each (1+1, or 6+6), but they can produce a 7 in six different ways (1+6, 2+5, 3+4, 4+3, 5+2, 6+1). That's why 7 is the most common result on 2d6, and why the distribution of any multi-dice sum forms a bell-shaped curve that clusters around the middle, even though each individual die is perfectly uniform. The distribution panel on this tool lets you watch that pattern build in real time — roll a handful of 2d6 and you'll start to see totals near 7 come up noticeably more than totals near 2 or 12, purely from the number of ways each sum can be formed.
This is also why a d20-based system like Dungeons & Dragons deliberately uses a single die instead of summing several smaller ones: a single d20 stays perfectly flat, giving every roll from 1 to 20 identical odds, which keeps critical successes and critical failures rare but exactly as rare as intended, rather than clustering probability toward the middle of the range.
Board Games and Everyday Uses Beyond the Tabletop
Plenty of classic board games lean on a single die or a pair of them — Monopoly, backgammon, and most children's games use 2d6, while games like Yahtzee use five d6 at once, which this dice roller handles in one click by setting the count to 5. If a physical die has gone missing from a game box, or you're playing remotely with friends over a video call and nobody wants to hold dice up to a webcam, this tool stands in perfectly, and everyone watching the same screen sees the identical result at the identical moment.
Beyond games, a dice roller is a genuinely handy everyday decision-making tool. Splitting a chore by rolling a d6 for "lowest roll takes out the trash," deciding who orders first at a restaurant with a quick d20 roll, or settling a disagreement about which movie to watch by assigning each option a number and rolling — these are all legitimate uses for a fair, fast random number generator, and they come up more often than people expect once the tool is one click away.
Common Mistakes to Avoid
- Forgetting the modifier sign. A modifier of "-2" must include the minus sign — leaving it blank or typing "2" when you meant a penalty will add instead of subtract.
- Reading percentile dice wrong. A d100 roll of "0" on this tool is shown as 100, matching standard tabletop convention where two zeros on percentile dice represent 100, not 0.
- Assuming a "cold streak" means the dice are broken. A d20 not showing a natural 20 for thirty rolls in a row is well within normal probability — the odds of that particular streak are around 21%, not vanishingly small.
- Mixing up sum probability with single-die probability. The face distribution panel tracks individual die faces, not the combined total — don't confuse the two when reasoning about how "likely" a given roll felt.
- Losing track of a long session. Use the roll history panel rather than trying to remember several rolls back — memory is far less reliable than the logged list.
This dice roller is one of dozens of free browser tools we've built and given away. If your business needs a website, SEO, or marketing help, we'd love to talk.
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Pair this dice roller with our coin flip simulator for the simplest possible fair random decision, or the random picker wheel to draw a name instead of a number. If a board game night just turned into a pizza order, our pizza size comparison tool settles which size is the better deal. To dig into the math behind any of these, see our probability calculator and percentage calculator, or browse the full free online tools hub.
Frequently Asked Questions
You can roll between 1 and 10 dice in a single click, in any combination of the standard tabletop sizes: d4, d6, d8, d10, d12, d20, and d100. Each die is rolled independently and shown individually alongside the combined total.
It means roll two six-sided dice, add their results together, then add 3. Set "Number of dice" to 2, "Dice type" to d6, and "Modifier" to 3, and this dice roller performs exactly that calculation, showing both dice individually and the final total.
It uses crypto.getRandomValues(), the browser's cryptographically secure random number generator, rather than the more predictable Math.random() function. Each face of each die has an equal, independently generated chance of appearing on every roll.
Because there are more ways to combine dice into a middle value than an extreme one. With two six-sided dice, a 7 can be made six different ways, while a 2 or a 12 can each only be made one way — so 7 comes up far more often even though every individual face is equally likely.
A d100 produces a result from 1 to 100, traditionally rolled physically as two ten-sided dice — one representing tens, one representing ones — where a double-zero result is read as 100. This tool simulates that directly, generating a single number from 1 to 100 per die.
No. The history and face distribution are kept only in your browser's memory for the current visit, so they disappear when you close or refresh the tab. Nothing is uploaded or stored on any server.
This tool runs entirely in your browser using built-in JavaScript. Nothing you enter is uploaded, stored, or sent to any server.
