How this dice roller works
A die is rolled by picking one of its faces at random with equal probability. This tool does the same digitally: for each die you ask for, it draws a number between 1 and the number of sides — 1 to 6 for a d6, 1 to 20 for a d20, and so on — then lists every result and adds them into a total. If you set a modifier, it is added (or subtracted) from that sum.
To keep the odds fair, the roller uses your browser's cryptographically strong random source, crypto.getRandomValues, together with rejection sampling. Naively taking a random byte modulo the number of faces would slightly favour the lower faces; rejection sampling discards the few values that would cause that imbalance, so every face is exactly equally likely. If secure randomness is unavailable, it falls back to Math.random.
Dice notation (XdY+Z)
Tabletop games describe rolls with a compact shorthand called dice notation. You can type it directly into the notation box above.
| Notation | Meaning | Example result |
|---|---|---|
| 1d6 | Roll one six-sided die | 1–6 |
| 2d6 | Roll two six-sided dice, sum them | 2–12 |
| 3d6+2 | Roll three d6 and add 2 to the total | 5–20 |
| 1d20+5 | Roll one d20 and add 5 (a typical D&D attack roll) | 6–25 |
| 1d100 | Roll percentile dice (1–100) | 1–100 |
Reference note: X is the number of dice, Y is the number of sides per die, and Z is an optional modifier added to (+) or subtracted from (−) the total. The modifier applies once to the whole roll, not to each die.
Frequently asked questions
- How does the dice roller work?
- Pick a dice type (such as d6 or d20) and how many dice to roll, then press Roll. The tool generates a random result for each die using your browser's secure random number generator, shows every die result, and adds them up — applying any modifier you set.
- Is the dice roller truly random?
- It uses crypto.getRandomValues, your browser's cryptographically strong random source, with rejection sampling so every face is equally likely and there is no bias toward any number. If that source is unavailable, it falls back to Math.random.
- What is dice notation like 3d6?
- Dice notation is written as XdY+Z. X is the number of dice, Y is the number of sides per die, and the optional +Z or -Z is a modifier added to the total. So 3d6+2 means roll three six-sided dice and add 2 to the sum.
- What dice can I roll?
- You can roll the standard polyhedral set used in tabletop games: d4, d6, d8, d10, d12, d20 and d100 (percentile). Each die is numbered from 1 up to its number of sides.
- Can I roll multiple dice at once?
- Yes. Choose how many dice to roll (for example 1 to 20) and the tool rolls them together, lists each individual result, and shows the combined total plus any modifier.
- Is this good for D&D and board games?
- Yes. It supports the dice and notation used in Dungeons & Dragons and most tabletop and board games, including the d20 and rolls like 1d20+5 or 2d6, so you can play without physical dice.