Dice Roller

What is a dice roller?

A dice roller is a tool that simulates rolling physical dice, returning a random result for each die plus their combined total. This one rolls any number of dice from 1 to 100, in a die type you choose — d4, d6, d8, d10, d12, d20 or d100 — and lets you add an optional modifier to the total. After each roll it shows the total and a list of each individual die, so you can use it exactly as you would a handful of real dice. Every roll happens locally in your browser.

What does this tool do?

It replaces a bag of dice with three inputs and a button. You set how many dice to roll, pick the number of sides (the die type), and optionally enter a modifier that is added to the sum. Click Roll and the tool generates a fresh random value for each die, adds them up, applies the modifier, and displays the result in two boxes: the grand Total and the Each die breakdown listing every face that came up.

The notation tabletop players use is “NdS”: N dice of S sides. So 2d6 means two six-sided dice, 1d20 means one twenty-sided die, and 3d8 means three eight-sided dice. With a modifier, 1d20+3 means roll one d20 and add 3 to the result. This tool covers all of those directly.

How does it work?

There is no single arithmetic formula — the method is repeated random sampling. For each of the N dice, the tool draws one uniform random integer in the range 1 to S (where S is the number of sides), then sums the N results and adds the modifier.

The core steps are:

1. Generate each die. For a die with S sides, the tool calls the browser’s crypto.getRandomValues to obtain a random number, then maps it into the range 1 to S so every face is equally likely. This is a cryptographically secure source, not the predictable Math.random, which keeps the rolls fair and unbiased.
2. Sum the dice. It adds the N individual results together to get the base total.
3. Apply the modifier. The modifier (which may be positive, negative or zero) is added to that base sum to produce the final Total.

A few terms and units worth pinning down:

• Sides (S): the die type, i.e. how many faces it has. A d6 has 6 sides numbered 1 to 6; a d20 has 20; a d100 has 100.
• Count (N): how many dice you roll at once. It is clamped to the range 1 to 100, so a blank or zero becomes 1, and a value above 100 becomes 100.
• Modifier: a flat whole number added to the total after the dice are summed. A modifier of 0 changes nothing; a negative modifier subtracts.

Because each die is sampled independently, the possible total for N dice of S sides runs from N (every die shows 1) up to N × S (every die shows S), and the modifier shifts that whole range up or down. For example, 2d6 alone ranges from 2 to 12, and adding a +3 modifier shifts it to 5 to 15.

Examples

Each example follows the exact method above: a uniform 1-to-S result per die, summed, then the modifier added. Because the dice are random, your specific numbers will differ each time — these show the rules and the possible range, not a fixed outcome.

Example 1 — 2d6 (dice = 2, sides = 6, modifier = 0). The tool rolls two dice, each a number from 1 to 6, and shows them under “Each die” along with their sum as the Total. A roll might come up 4, 2 for a Total of 6. The Total can be anywhere from 2 (both dice show 1) to 12 (both show 6).

Example 2 — 1d20+3 (dice = 1, sides = 20, modifier = 3). The tool rolls one twenty-sided die for a value from 1 to 20, then adds 3. If the die lands on 14, the Total is 17 (14 + 3). Across all outcomes the Total ranges from 4 (a 1 plus 3) to 23 (a 20 plus 3).

Example 3 — 3d8 (dice = 3, sides = 8, modifier = 0). The tool rolls three eight-sided dice, each from 1 to 8, lists all three under “Each die”, and shows their sum as the Total. A roll of 5, 1, 7 gives a Total of 13. The Total can range from 3 (all three show 1) to 24 (all three show 8).

Example 4 — 4d6 with a negative modifier (dice = 4, sides = 6, modifier = -2). The tool rolls four d6, sums them, then subtracts 2. If the four dice total 18, the result shows 16 (18 − 2). The Total ranges from 2 (four 1s minus 2) to 22 (four 6s minus 2).

Die type reference

This table lists each die type the tool supports, the range of a single die, and the possible total range for one die before any modifier. The modifier simply shifts these totals up (positive) or down (negative).

Die type	Sides (S)	Single die range	Total of 1 die
d4	4	1 to 4	1 to 4
d6	6	1 to 6	1 to 6
d8	8	1 to 8	1 to 8
d10	10	1 to 10	1 to 10
d12	12	1 to 12	1 to 12
d20	20	1 to 20	1 to 20
d100	100	1 to 100	1 to 100

For N dice of any type, multiply the upper bound by N: the minimum total is always N and the maximum is N × S. So 5d10 ranges from 5 to 50, and 2d20 ranges from 2 to 40, each before the modifier is applied.

Common uses

A virtual dice roller is handy anywhere real dice would be — and especially when you do not have them on hand:

• Tabletop role-playing games — roll d20 attack and skill checks, d6 and d8 damage, or a d100 percentile, with a modifier for your bonus, for D&D, Pathfinder and similar systems.
• Board games and card games — replace a lost or missing die so play can continue, from a single d6 to several at once.
• Teaching probability — demonstrate ranges, sums and distributions by rolling 2d6 or 3d6 many times and watching the totals cluster.
• Fair decisions and random picks — assign a number to each option and roll a die that covers them to choose without bias.

Tips and common mistakes

A few pointers to get accurate results and avoid surprises:

• Match the notation to the inputs. For 1d20+3, set dice to 1, sides to 20 and modifier to 3 — do not put the modifier in the dice count. The modifier is a separate field.
• The modifier is added once to the total, not to every die. 3d6+2 rolls three dice and adds 2 to the combined sum, giving a range of 5 to 20, not 2 added to each die.
• Use a negative modifier to subtract. Enter -1 (or any negative value) to apply a penalty; the result shows the dice sum minus that amount.
• Read “Each die” to verify a roll. If you need to know which die scored high (for example, the highest single d6), check the breakdown rather than only the total.
• Roll again for a new result. Each click is independent, so a previous high or low roll does not make the next one more or less likely.

Limitations and notes

This tool simulates fair, independent dice: every face is equally likely on each roll, and one roll never influences the next. The die types are fixed to the seven standard polyhedral options (d4 through d100), so it does not offer non-standard dice, custom faces, or rules like “drop the lowest”, exploding dice or rerolls — combine or read the individual results yourself if your game needs those. The dice count is capped between 1 and 100 per roll, and the modifier is a single whole number applied once to the total. Results are not saved, so there is no roll history beyond the most recent roll on screen. Everything runs privately in your browser: each die is generated locally with crypto.getRandomValues, so nothing about your rolls is uploaded, logged or stored, and the roller keeps working offline once the page has loaded.

For more random and decision tools, pair this with the coin flip for a quick yes-or-no, the random number generator for any range you like, or the magic 8 ball for a fortune-style answer — and if you need to crunch the odds, try the percentage calculator or browse the full fun and random collection.