Dice Roller — d4 to d100, Dice Notation, Advantage and Drop-Lowest
Roll any dice with standard notation like 2d6+3 or 4d6dl1, see every die, and keep a history — fair rolls from cryptographic randomness.
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NdS + modifier · several terms: 2d6+1d4+2 · keep/drop: kh keep highest, kl keep lowest, dl drop lowest, dh drop highest.
Roll dice online using the notation every tabletop game uses: d20, 2d6+3, 1d8+1d4, 4d6dl1 (roll four, drop the lowest), 2d20kh1 (advantage). Every die is shown individually with maximums and ones highlighted, dropped dice struck through, and the total large enough to read across a table. Rolls use the browser's cryptographic generator, so each face really is equally likely.
How to use Dice Roller
- Tap a preset (d20, 2d6, advantage, stats…) or type notation and press Roll or Enter.
- Read the total and the individual dice underneath; dropped dice are crossed out.
- The history keeps the last dozen rolls for the session.
Dice notation
NdS rolls N dice with S sides and adds them: 3d6 is three six-sided dice. A missing N means one die: d20. Add or subtract flat numbers and other dice: 2d6+1d4+2, 1d20-1. d% is a percentile die (1–100).
Keep and drop modifiers follow the dice: kh1 keep the highest one, kl1 keep the lowest one, dl1 drop the lowest one, dh1 drop the highest. So D&D advantage is 2d20kh1, disadvantage 2d20kl1, and the classic ability-score roll is 4d6dl1.
Why "fair" needs saying
Mapping a random number onto six faces is easy to get slightly wrong: take a 32-bit random value modulo 6 and faces 1–4 come up a hair more often than 5–6. This roller uses rejection sampling — it throws away the sliver of values that would bias the result — on top of the browser's cryptographic generator. The bias it avoids is tiny (parts per billion) but the fix costs nothing, and "the dice are fair" should be true, not approximately true.
Odds worth knowing
- 2d6 peaks at 7 (one in six); 2 and 12 are one in thirty-six each.
- Advantage on a d20 raises the average from 10.5 to 13.8 and roughly doubles the chance of a natural 20.
- 4d6 drop lowest averages 12.24 — which is why point-buy systems start characters lower.
- Three d6 make a rough bell curve; a single d20 is flat. Games choose deliberately.
For a single random number in any range, the random number generator; for a two-sided decision, the coin flip.
Frequently asked questions
How do I roll with advantage?
Type 2d20kh1 (two d20, keep the highest one) or tap the Advantage preset. Disadvantage is 2d20kl1. The dropped die is shown crossed out so you can see both.
How do I roll ability scores?
4d6dl1 — four six-sided dice, drop the lowest — is the standard method; roll it six times. The Stats preset does one set.
Can I add different dice together?
Yes: 1d8+1d4+3 for a weapon plus a bonus, 2d6-1, and so on. Each group is shown separately with its subtotal, and the total combines them with any modifiers.
Are the rolls truly random?
They come from the browser's cryptographic random generator with rejection sampling, so every face is exactly equally likely. There is no seed to predict and no server involved.
What is d% or d100?
A percentile roll from 1 to 100. Tabletop games traditionally roll it with two ten-sided dice (tens and units); here it is one uniform draw, which is the same distribution.