How dice are rolled
Each die is rolled independently using crypto.getRandomValues, the browser's cryptographic-grade random number source. Modulo bias (where the lowest few values are slightly more likely with a naive %) is eliminated by rejection sampling. The result is statistically indistinguishable from physical fair dice.
For d6, each face is shown as the traditional pip pattern. For d4, d8, d10, d12, d20, and d100, the numerical result is shown in a square. A natural max (e.g., 20 on a d20) is highlighted gold (a "crit"); a natural 1 on a d20 is highlighted red (a "fumble"). Both are tabletop conventions.
Common dice patterns
| Notation | Use case | Range |
|---|---|---|
| 1d6 | Single classic die roll (Monopoly, Yahtzee) | 1–6 |
| 2d6 | Sum of two dice (Risk, Catan, craps) | 2–12 (peak at 7) |
| 3d6 | Classic D&D ability score (1st edition) | 3–18 |
| 4d6 drop lowest | Modern D&D ability score | 3–18, biased toward higher |
| 1d20+5 | D&D 5e ability check with +5 modifier | 6–25 |
| 1d100 | Percentile roll (Call of Cthulhu, RuneQuest) | 1–100 |
FAQ
Why "Roll ×100"?
Use it to demonstrate the law of large numbers — over hundreds or thousands of rolls, the average per-die approaches the theoretical mean (3.5 for a d6, 10.5 for a d20). The "highest" and "lowest single" stats also start hitting their extremes more often as you roll more.
Can I roll mixed dice (e.g., 1d20 + 1d6)?
Not in a single roll — set up one type, roll, then change to the other and roll again. Add the totals manually. A future enhancement could parse "1d20+1d6+3" notation directly.
What about advantage / disadvantage?
Roll 2d20 and take the higher (advantage) or lower (disadvantage). The simulator shows each die individually, so it's easy to read off either value.