Keep and drop rules are calculated by counting every combination; very large pools are estimated from 200,000 simulated rolls and labelled as such.
Dice notation
| You type | Meaning |
|---|---|
d20 | One 20-sided die |
3d6+2 | Three six-sided dice plus 2 |
1d8+1d6-1 | Mixed dice and a modifier |
4d6dl1 or 4d6kh3 | Roll four d6, drop the lowest (keep the highest three) |
2d20kh1 / 2d20kl1 | Advantage / disadvantage |
d% or d100 | Percentile die, 1 to 100 |
How the rolls and odds work
DiceKit draws each die from your browser's cryptographic random number generator (crypto.getRandomValues), using rejection sampling so no face is favoured. Nothing is sent anywhere. The odds are exact: plain dice are combined one at a time (a convolution of their distributions), and keep or drop rules are calculated by counting every possible combination. Only very large keep or drop pools are estimated by simulation, and the result says so.
Handy averages
| Dice | Average | Range |
|---|---|---|
| d6 | 3.5 | 1–6 |
| 2d6 | 7 | 2–12 |
| 3d6 | 10.5 | 3–18 |
| 4d6 drop lowest | 12.24 | 3–18 |
| d20 | 10.5 | 1–20 |
| d20 with advantage | 13.83 | 1–20 |
| d20 with disadvantage | 7.18 | 1–20 |
| 8d6 | 28 | 8–48 |
Frequently asked questions
What is the most likely total on 2d6?
7, with a 1 in 6 (16.67%) chance.
What are the odds of rolling 18 on 3d6?
1 in 216, about 0.46%.
What is the chance of at least one 6 on two dice?
11 in 36, about 30.6%.
Is DiceKit free?
Yes, with no sign-up or ads.
Is my roll history saved?
Yes, in this browser only, and you can clear it at any time.