Dice Roller

The Dice Roller rolls any number of virtual dice (d4, d6, d8, d10, d12, d20, or d100) with a cryptographically-fair result and a running total. Perfect for board games, tabletop RPGs like D&D, and the classroom when you don’t have physical dice handy. Each roll draws a 32-bit value from the Web Crypto API's crypto.getRandomValues and applies rejection sampling — discarding any value that falls above the largest multiple of the die's side count, then reducing the rest modulo the number of sides — which removes the small bias a naive "value % sides" approach would introduce. If Web Crypto isn't available in the browser, the tool quietly falls back to Math.random() instead. The tumble animation shown while rolling (up to 20 dice, roughly eight refreshes every 70ms) draws genuine additional random rolls purely for visual effect before settling on the one true result that gets reported and totaled.

Beginner⏱ 10 secondsUpdated 2026-07-09

Die type

How many dice

Roll up to 20 dice (d4, d6, d8, d10, d12, d20, or d100) at once. Every roll is cryptographically fair — a true, unbiased result — perfect for board games, tabletop RPGs, and classroom use. Runs entirely in your browser.

How This Tool Works

Pick your die type (d4 through d100) and how many to roll, then press Roll. Each die shows its value and, when you roll more than one, the total is added up for you.

Formula & Method

Each die uses your browser’s cryptographically-secure random generator with rejection sampling, giving every face an exactly equal probability — a true, unbiased roll.

Example Calculation

Rolling 3d6 might produce 4, 1, 6 for a total of 11, while a single d20 saving throw might land on 17 — each face drawn independently and with exactly equal probability via rejection-sampled crypto.getRandomValues, not a plain modulo of Math.random().

Please note: This calculator provides estimates for general informational purposes only. Results may not be accurate for every situation — use your judgment and consult a relevant professional when it matters.

About the Dice Roller

Dice are the simplest random-number machines people have, and tabletop games, classroom probability lessons, and role-playing campaigns all depend on them. This roller covers the standard set of polyhedral dice: the four-sided d4, the familiar six-sided d6, the eight-sided d8, the ten-sided d10, the twelve-sided d12, the twenty-sided d20, and the d100 for percentile results. You choose the die type, pick how many to roll up to twenty, and press the roll button to see each die's value and, for more than one die, the combined total.

Each die is rolled independently. The tool asks your browser for a random 32-bit number and then converts it to a face value from 1 up to the number of sides. To make sure no face is even slightly favored, it discards the small slice of numbers at the top of the range that would otherwise cause some faces to appear a hair more often than others. The result is that every face on every die is equally likely, and one die's result has no influence on another's or on your earlier rolls.

A short tumbling animation runs for a little over half a second before the final values settle, and the totals appear after that. The tool is intentionally plain. It does not apply modifiers, drop the lowest die, track advantage and disadvantage, or keep a history, so it works best as a fast stand-in for physical dice whenever the dice you own are missing, hard to read across a video call, or too noisy for the room.

When to Use It

Running a tabletop role-playing session online

A game master on a video call needs everyone to trust the rolls. Players take turns pressing the roll button for a d20 attack or a 3d6 ability check on a shared screen, and the whole table sees the same numbers. Adding any bonuses is done mentally, since the tool shows the raw die values and the total.

Board games with missing dice

Someone opens an older board game and finds the dice are lost. Setting the die type to d6 and the count to two reproduces a standard pair, with the total displayed automatically. It saves a trip to the store, and the same tool also handles games that need a single d6 or a handful of them.

Teaching probability in a classroom

A math teacher asks students to predict the most common sum of two dice, then rolls two d6 dozens of times on the projector and tallies the totals. Students see that 7 shows up more often than 2 or 12, and the connection between 36 equally likely pairs and the distribution of sums becomes concrete.

Generating percentile results

A player needs a result from 1 to 100 for a random table, such as a loot or encounter chart. Choosing d100 and rolling a single die returns a number in that range directly, without having to combine two ten-sided dice and decide how to read the 00 result.

How to Use It, Step by Step

Under Die type, click one of the buttons labeled d4, d6, d8, d10, d12, d20, or d100. The selected die is highlighted. The roller starts on d6, and the number after the d is the number of faces.
Under How many dice, type a whole number from 1 to 20 into the box, or use the minus and plus buttons beside it. A value outside the range is corrected automatically, and clearing the box resets it to 1.
Read the button below the controls. It tells you exactly what will be rolled, for example Roll 2 x d6 or Roll d20, so you can confirm your choice before pressing it.
Press the roll button. The numbers change quickly for roughly half a second to simulate tumbling, and the button reads Rolling and is disabled while this happens.
Read the individual values shown as boxed numbers. Each box is one die. They are displayed in the order they were rolled, which has no special meaning because all dice are rolled together.
If you rolled more than one die, read the Total shown under the boxes after the animation ends. It is a simple sum of the faces and does not include any modifiers.
Add any bonuses or penalties yourself. For example, a d20 plus a 5 bonus in a role-playing game means taking the displayed number and adding 5 before comparing with the target.
Roll again by pressing the same button. Changing the die type does not erase the previous numbers on screen until you roll again, so check that the numbers match the current die type.

Understanding Your Results

Every die box shows a whole number from 1 up to the die's number of faces. A d10 gives 1 to 10 rather than 0 to 9, and a d100 gives 1 to 100. The Total line appears only when you roll two or more dice and is the sum of all the boxes. If you roll one die, the single number is the result and no total is shown.

To check whether a result is typical, compare it with the expected value. A single die averages the sum of its faces divided by the number of faces, which is 3.5 for a d6, 10.5 for a d20, and 50.5 for a d100. Multiply by the number of dice to get the average total: four d6 average 14, and five d8 average 22.5. Totals bunch toward the middle when you roll several dice, while a single die is equally likely to land on any face.

Remember that independent rolls have no memory. A d20 that has just rolled a 1 is no more or less likely to roll a 1 next time, and a long streak of low numbers does not make high numbers more likely. If you need the probability of reaching a target, count the favorable outcomes and divide by the total number of outcomes, or use a probability table for the dice you are using.

More Worked Examples

A d20 check against a target number

Scenario: Choose d20, set the count to 1, and roll to beat a difficulty of 15 or higher.

The roller returns one number from 1 to 20. Each face has a one in twenty chance, 5 percent. The faces that meet a target of 15 or more are 15, 16, 17, 18, 19, and 20, which is six faces out of twenty, so the chance of success is 6 / 20 = 30 percent. If you roll a 17 and your character has a bonus of 3, you compare 20 against the target yourself, since the tool shows only the raw 17.

Rolling 3d6 for a character stat

Scenario: Choose d6, set the count to 3, and press the roll button once.

The tool shows three boxes, each from 1 to 6, and a Total between 3 and 18. There are 6 x 6 x 6 = 216 equally likely outcomes. A total of 3 or 18 can happen only one way each, a probability of about 0.46 percent. Totals of 10 and 11 are the most common, at 27 of 216 outcomes each, or 12.5 percent each, and the average is 10.5. Totals from 9 to 12 together account for 104 of the 216 outcomes, about 48.1 percent.

Why a pair of dice favors seven

Scenario: Choose d6, set the count to 2, and roll many times for a classroom tally.

Each roll shows two boxes and a Total from 2 to 12. There are 36 equally likely pairs. A total of 7 can come from six pairs (1+6, 2+5, 3+4, 4+3, 5+2, 6+1), so it appears about 16.7 percent of the time. A total of 2 or 12 comes from a single pair each, about 2.8 percent. Over dozens of rolls the tally should lean toward 7, though small samples will wobble around these percentages.

Tips for Better Results

Count the dice and sides before you roll. The label on the roll button, such as Roll 4 x d6, is an easy final check that you set the same dice your game's rule calls for.
For percentile tables that ask for two ten-sided dice, a single d100 roll gives the same range of 1 to 100 with every value equally likely, so you can skip the combination step.
When you need the highest or lowest of several dice, roll them together and read the individual boxes. The tool does not drop or keep dice automatically, but all values are visible for you to choose from.
In classroom demonstrations, predict the outcome first and record it. Students learn more from seeing their guess compared to a real set of rolls than from watching rolls without a prediction.
Roll all the dice for a turn in a single press instead of pressing repeatedly until you like the number. Re-rolling for a better result defeats the purpose of random dice and can change how a game plays.
If a rule says to add a modifier, write the raw total and the modifier separately on paper or in chat. That way other players can verify the roll and the arithmetic, which avoids disputes.

Common Mistakes to Avoid

Assuming a d10 includes zero. This roller returns 1 to 10 on a d10, so if your game uses 0 to 9, subtract 1 or treat a 10 as 0 according to your rule book.
Forgetting the dice count limit. The tool rolls at most 20 dice at once, so a rule that asks for more than 20 requires splitting the roll into two or more presses and adding the totals.
Expecting a total on a single die. The total line appears only when two or more dice are rolled, since a single die's value already is the result.
Believing in a streak. A run of small numbers does not mean a big number is due, because each die has no memory of earlier rolls.
Reading dice before the animation finishes. The numbers change for about half a second, so wait until the button stops reading Rolling before you read or record a result.

Assumptions and Limits

Each face is treated as equally likely and each die as independent of the others. The tool does not model loaded dice, rerolls, exploding dice, or house rules, and it does not store a history of rolls.
The random numbers come from the secure generator in your browser. If a very old browser lacks it, the tool falls back to a standard generator, which is still fine for games but not designed for cryptographic use.
The totals shown are plain sums. Modifiers, advantage or disadvantage, dropped dice, and critical-hit rules from specific games must be applied by hand.
Probabilities quoted in guides such as this one are exact for fair dice and large numbers of rolls, but any small set of real rolls will differ from the percentages, as it should.

Key Terms

Polyhedral die: A die with a number of faces other than six, such as a d4, d8, d12, or d20. They are common in role-playing and wargames.
Notation (such as 3d6): Shorthand for rolling several dice. The first number is how many dice to roll, and the number after the d is how many faces each die has.
Expected value: The average result over many rolls. For one die it is the mean of its faces, for example 3.5 for a d6.
Percentile die: A d100 or a pair of d10s that produces a result from 1 to 100, often used for tables and percentage chances.
Rejection sampling: A technique that throws away random numbers falling in a leftover range so that every outcome ends up equally likely, avoiding a subtle bias.
Independent events: Events where one result does not change the odds of another. Rolling dice repeatedly is a standard example.

Frequently Asked Questions

Which dice can I roll?+

The standard polyhedral set — d4, d6, d8, d10, d12, d20 — plus d100, and up to 20 dice at once.

Are the rolls truly random?+

Yes — they use your browser’s secure random generator with rejection sampling, so every face is exactly equally likely with no bias.

Does it total multiple dice?+

Yes — roll several dice and the sum is calculated automatically, which is handy for tabletop games.

Why use crypto.getRandomValues with rejection sampling instead of just Math.random()?+

Taking a random 32-bit integer modulo the number of sides on its own introduces a tiny bias toward lower face values, because 2³² isn't evenly divisible by most side counts. Rejection sampling discards the small leftover slice of values that would cause that bias before taking the modulo, so every face comes out exactly equally likely.

Does the rolling animation affect my actual result?+

No — the animation cycles through several genuine random rolls purely for visual tumble effect, then stops on the roll that's actually recorded as your result and added to the total. What you see settle on screen is the true, final value.

Are virtual dice as fair as physical dice?+

In practice they can be fairer. Physical dice have tiny imperfections, uneven edges, drilled pips, or wear, and cheap dice can show measurable bias over thousands of rolls. A good random number generator with correction for bias has no such physical flaws. Real dice remain a pleasure to use, but for a simple, repeatable fair roll on a screen, virtual dice are entirely suitable.

What is the most likely total when I roll several dice?+

The total closest to the average is the most likely, and the distribution looks like a bell shape as you add dice. For two six-sided dice it is 7, for three it is 10 and 11 equally, and for four it is 14. With more dice, totals near the middle become much more common than totals near the minimum or maximum, which is why extreme results are rare.

How do I roll with advantage or disadvantage?+

Set the die to d20 and the count to 2, then press roll. With advantage, use the higher of the two numbers shown, and with disadvantage, use the lower one. Because both values are displayed, you can read the right one directly, though you will need to ignore the total line, which adds the dice together and is not used for that rule.

Why does the d100 give a single result instead of two dice?+

A physical d100 is usually two ten-sided dice, one for tens and one for ones. This tool represents it as a single hundred-sided die for simplicity. The result is still uniformly distributed from 1 to 100, with each value having a 1 percent chance, so it works the same way for percentile tables without any reading convention.

Can I use this tool for gambling or high-stakes drawings?+

It is designed for games and teaching, not for regulated gambling or official drawings. It keeps no record, offers no audit trail, and runs entirely in your browser, so no one else can verify what happened. If money or prizes of real value depend on the result, use a method that your rules or local regulations accept, such as a certified system or physical dice witnessed by the participants.

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