The formula
How it works
Roll any number of dice with any number of sides. Choose how many dice and which type — from a d4 to a d100 — add an optional modifier, and press Roll for a fresh result.
FAQ
What do d6, d20 and d100 mean?
The number after the “d” is how many sides the die has, so a d6 is an ordinary cube numbered 1 to 6, a d20 is the twenty-sided die used in many tabletop games, and a d100 gives a percentage from 1 to 100. Each side is equally likely on every roll.
What is the modifier for?
Many games add a fixed bonus or penalty to a roll — for example “roll 2d6+3”. Enter that number as the modifier and it is added to (or, if negative, subtracted from) the total of the dice. Leave it at zero for a plain roll.
Is the roll actually random and fair?
Each die uses a uniform random number generator, so every side has an equal chance on every roll, just like a physical die. Rolls are independent, so a previous result never influences the next one.
Can I use a negative modifier?
Yes — enter a negative number and it is subtracted from the total, for example “roll 1d20−2”. The breakdown shows the modifier with its sign so you can see exactly what was added or removed.
How do I roll mixed dice, like 1d20 and 2d6 together?
This tool rolls one die type at a time, so roll each type separately and add the totals yourself. Many games list mixed rolls this way anyway, such as “1d20+2d6”.
Why do the totals cluster in the middle when I roll several dice?
Summing multiple dice produces a bell-shaped spread rather than a flat one, because there are many more combinations that add up to a middle value than to the extremes. A single die stays flat, but 2d6 or more starts to cluster around its average.
Is there a limit to how many dice or sides I can use?
You can roll up to 30 dice at once, and any number of sides down to a minimum of 2, covering everything from a coin-flip d2 up to a d100. That range covers virtually every tabletop game’s dice notation.
About the dice roller
This tool rolls virtual dice for you: pick how many dice and which type, from a four-sided d4 up to a hundred-sided d100, optionally add a modifier, and press Roll. It shows each individual die and the total, mirroring the “2d6+3” notation used in board games and role-playing games. It is a handy stand-in whenever real dice are not to hand.
How to use it
Set the number of dice, choose the die type from the list, and enter a modifier if your game uses one. Press Roll to see the result, and roll again for a new one. For example, two six-sided dice (2d6) give a total from 2 to 12, and adding a +3 modifier shifts that range to 5 to 15. Every roll is independent of the last.
The formula
Each die is an independent random whole number from 1 to its number of sides. The total is the sum of all the dice plus the modifier, . Because the dice are summed, the middle totals are far more likely than the extremes — rolling 2d6 gives a 7 six times as often as a 2 or a 12, which is why summed dice feel different from a single flat roll.
Where it is used
Players use it for board games and tabletop role-playing when the physical dice have gone missing, for games that call for unusual dice like a d20 or d100, and for teaching probability with clear, repeatable rolls. It is also handy for making quick random decisions. Because it faithfully reproduces standard dice notation, it slots straight into any game that specifies rolls that way.