Dice Roller
Choose how many dice to roll and how many sides each has, then press Roll. You see every die, the total, the average per die and the range that was possible, and your last ten rolls stay in a history list. Presets cover the standard tabletop set. Free, no sign-up, and nothing leaves your browser.
Number of dice
Sides per die
Rolling 2d6
How to Use the Dice Roller
- 1. Set the number of dice. From 1 to 20. Every die in a roll has the same number of sides.
- 2. Pick the sides. Use a preset — d4, d6, d8, d10, d12, d20 or d100 — or type any whole number from 2 to 1,000 in the Custom box.
- 3. Roll. The button names the roll for you, such as Roll 2d6. Each die appears separately, with the total beneath.
- 4. Read the stats and history. The cards show the total, the average per die and the minimum and maximum a roll like this could produce, and the list below keeps your last ten rolls, newest first, as 2d6: 3+5 = 8. Clear wipes them.
Reading Dice Notation
Dice are written NdS: N is how many dice to roll and S is how many sides each has. So 3d6 is three six-sided dice added together and 1d20 is a single twenty-sided die. A third part, as in 1d20+5, adds a fixed modifier to the total. This roller does the first two parts only; add any modifier yourself, and for advantage or disadvantage roll 2d20 and read the higher or lower die. A d10 here shows 1–10 and a d100 shows 1–100; some tabletop games use 0–9 and 00–90 percentile dice instead, so adjust if your rules require it.
The Odds Behind the Dice
A single fair die gives every face the same chance, 1/S, and averages (S + 1) / 2: 3.5 for a d6, 10.5 for a d20. Add dice together and the totals stop being equal, because some totals can be made in more ways. With 2d6 there are 36 equally likely pairs:
| Total of 2d6 | Ways to roll it | Chance |
|---|---|---|
| 2 or 12 | 1 each | 2.8% each |
| 3 or 11 | 2 each | 5.6% each |
| 4 or 10 | 3 each | 8.3% each |
| 5 or 9 | 4 each | 11.1% each |
| 6 or 8 | 5 each | 13.9% each |
| 7 | 6 | 16.7% |
More dice pull the total toward the middle. Three d6 average 10.5 and total 18 only once in 216 rolls (0.46%), while a total of 15 or more comes up 20 times in 216 (9.3%). The spread of a sum of N dice grows only with √N, which is why bell curves appear so quickly — a standard demonstration of the central limit theorem. Some other numbers worth knowing: a single d20 shows 15 or higher 30% of the time, and the chance of at least one six in four rolls of a d6 is 1 − (5/6)4 ≈ 51.8%.
Classroom experiment
Predict the most common total for 2d6, then roll 2d6 thirty times and tally the totals on paper — the history list keeps only the last ten. A triangle peaking at 7 starts to appear within a few dozen rolls, and pooling the whole class's tallies shows it clearly.
How the Dice Are Rolled
Each die is a whole number from 1 to the number of faces, drawn from your browser's cryptographic random source (crypto.getRandomValues) with rejection sampling: the page discards the uneven tail of the generator's range, so every face of a d6, d20 or d100 is exactly as likely as any other, and no roll depends on the one before. It is a software-generated draw rather than a physical die or a certified one, which is fine for games and lessons. Results are decided when you press the button, and the Minimum and Maximum possible cards describe the dice that were just rolled, not the sides setting you may have changed since.
Which Tool Do You Need?
| If you want… | Use |
|---|---|
| Dice of one size, added up, with a history | This Dice Roller |
| Two outcomes and a running tally of streaks | Coin Flip |
| A list of numbers from a range, with or without repeats | Random Number Generator |
| Cards dealt from a deck without being replaced | Random Card Draw |
| A pick from options you name yourself | Wheel Spinner |
| Exact probabilities and expected values for a game | Expected Value Calculator |
Frequently Asked Questions
- How do I roll dice online?
- Set the number of dice, choose the sides with a preset button or the Custom box, and press Roll. The individual dice, their total and the roll's average appear straight away, and the roll is added to the history.
- What does 3d6 mean?
- It means rolling three six-sided dice and adding the results. The number before the d is how many dice, and the number after it is how many sides each die has. 1d20 is one twenty-sided die, and 2d10 is two ten-sided dice.
- Are the dice rolls fair?
- Every face has an exactly equal chance on each roll, and no roll depends on an earlier one. The dice use your browser's cryptographic random source with rejection sampling: ideal for games, classroom demonstrations and tabletop sessions, though a software draw rather than a physical or certified one.
- Which dice can I roll, and how many?
- Presets cover d4, d6, d8, d10, d12, d20 and d100, and the Custom box accepts any whole number of sides from 2 to 1,000. You can roll up to 20 dice at once, all with the same number of sides. A roll cannot mix dice of different sizes.
- Can I add a modifier or roll with advantage?
- Not directly. Add the modifier to the displayed total yourself. For advantage or disadvantage, roll 2d20 and take the higher or the lower die; both dice are shown separately so you can read them.
- What is the most likely total when I roll two dice?
- For 2d6 it is 7, which can be made six ways out of 36 (16.7%). Totals of 2 and 12 can be made only one way each (2.8%). In general the most likely sum of several dice is the middle of the range.