Dice roller: roll d6, d20 and more online
No dice at hand? This dice roller lets you roll a dice online in one click: pick how many and which kind, then roll. You see every die (the d6 with dots), the total, your last 12 rolls and how likely each total is. For tabletop games, type dice notation such as 3d6+2 or roll with advantage.
Source: W3C Recommendation, W3C Web Cryptography API – getRandomValues(). Updated: .
How it is calculated
Dice notation: 3d6+2, keep highest, several sets
For role-playing games, type the roll into the dice notation box or build it with the +d4 … +d100 buttons. 3d6+2 rolls three six-sided dice and adds 2 (possible total 5–20, average 12.5). 4d6kh3 rolls four dice and keeps the three highest – the usual way to roll ability scores (average 12.24); kl keeps the lowest. Separate several rolls with commas, e.g. 1d20+5, 2d6+3 for attack and damage: each set gets its own total. With advantage or disadvantage every set is rolled twice and the higher or lower total counts. Dropped dice are shown faded and in square brackets. The Share button copies a link that opens the roller with exactly this set-up.
Each die shows every side with the same probability – 1/6 ≈ 16.67% for a d6, exactly 5% for a d20. The random numbers come from crypto.getRandomValues(), your browser's secure random number generator, and are scaled to the number of sides without bias.
Why 7 is the most common total with two dice
Two d6 give 6 × 6 = 36 equally likely combinations. A total of 7 can be made six ways (1+6, 2+5, 3+4, 4+3, 5+2, 6+1), while 2 and 12 can only be made one way each. So 7 has a 6/36 = 16.67% chance, 2 only 1/36 = 2.78%. The "Probability of each total" table works this out exactly for any combination of dice – not estimated, but by counting every possibility.
Odds of rolling at least one 6
The chance that one d6 does not show a 6 is 5/6. With n dice, at least one 6 = 1 − (5/6)n.
| Dice | Math | At least one 6 |
|---|---|---|
| 1 | 1 − 5/6 | 16.67% |
| 2 | 1 − 25/36 | 30.56% |
| 3 | 1 − 125/216 | 42.13% |
| 4 | 1 − 625/1,296 | 51.77% |
Only from four dice on is a 6 more likely than no 6. The same holds for any other number from 1 to 6.
Average
The expected value of one die with s sides is (s + 1) ÷ 2; for n dice it is n × (s + 1) ÷ 2. Three d6 average 10.5, two d20 average 21.
Which dice for which game?
| Game | Dice |
|---|---|
| Ludo, Monopoly (2 dice), Catan (2 dice) | d6 |
| Yahtzee | 5 × d6 |
| Dungeons & Dragons 5e and other tabletop RPGs (full polyhedral set) | d4, d6, d8, d10, d12, d20 |
| Backgammon | 2 × d6 |
| Percentile roll / d100 | 2 × d10 (one for tens, one for ones) |
Odds of a Yahtzee: how likely are five of a kind?
Five d6 give 6⁵ = 7,776 equally likely outcomes. All five dice show the same number in exactly 6 of them (one for each possible number 1–6). So the chance of a Yahtzee on the very first roll is 6/7,776 ≈ 0.077%. The real game allows two re-rolls, which makes the actual per-turn odds much higher.
d100: rolling percentile dice
The d100 is built in: choose d100 as the type of die or type d100 into the notation box. With real dice, a d100 (percentile die, common in tabletop RPGs) can be simulated with two d10: set 2 × d10, read the first die as the tens digit and the second as the ones digit. The d10 here shows 1–10; count the 10 as 0. Example: 4 and 7 is 47, 10 and 3 is 03 = 3, two 10s is 00 = 100. That gives 100 equally likely results from 1 to 100.
Need a d3, a d30 or a modifier?
A d3 (1–3) is a d6 halved: 1–2 = 1, 3–4 = 2, 5–6 = 3 – each result keeps exactly 1/3. For unusual dice such as a d30, set the range 1 to 30 in the random number generator. Modifiers like 1d20 + 5 go into the notation box: type 1d20+5 and the roller adds them for you.
Only two outcomes? A coin flip will do. For bigger ranges use the random number generator.
Frequently asked questions
Is the online dice roller fair?
Yes. Every side is exactly equally likely. Physical dice are often slightly unbalanced; this roller uses the browser's cryptographically secure random number generator instead.
What does 2d6 mean?
d stands for die, the number after it for the number of sides. 2d6 means: roll two six-sided dice and add them up.
Can I spot doubles?
Yes, each die is shown separately, d6 with pips. The chance of doubles with two d6 is 6/36 = 16.67%.
How likely is a natural 20?
Exactly 1/20 = 5%. Rolling with advantage (two d20, keep the higher) gives at least one 20 with 1 − (19/20)² = 9.75%.
What are the odds of rolling a Yahtzee?
On the first roll of 5d6, exactly 6/7,776 ≈ 0.077%. With the two re-rolls allowed in the real game, the odds per turn are much higher.
Can I add modifiers like 1d20 + 5?
Yes. Type 1d20+5 into the dice notation box: the roller adds or subtracts the modifier and shows the working, e.g. 19 (14 + 5).
Is there a d100?
Yes. Choose d100 as the type of die or type d100 into the notation box; every number from 1 to 100 is equally likely. With real dice, roll two d10 and read one as the tens and one as the ones digit.
Which dice do I need for D&D 5e?
The classic polyhedral set – d4, d6, d8, d10, d12 and d20 – all of them are in this roller.
Sources and legal basis
- W3C Recommendation: W3C Web Cryptography API – getRandomValues()
- MDN Web Docs – Crypto.getRandomValues()
- Wikipedia: Dice notation (AdX+B, keep highest/lowest)
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