How to use the Dice Roller
- Set the number of dice (1 to 10) and pick the die type, from d4 to d100.
- Add a modifier if your game calls for one, such as +3 for an ability bonus.
- Press Roll dice, click the dice tray or press R on your keyboard.
- Read the total and each die’s value. Earlier rolls are listed in the history table.
Features
- Seven die types: d4, d6, d8, d10, d12, d20 and d100
- Roll up to 10 dice at once with a positive or negative modifier
- Fair results from cryptographically secure randomness
- Animated roll with classic pip faces for d6
- Lowest, highest and average result for every roll
- Roll history with timestamps, saved on your device
Dice notation explained
Tabletop games describe rolls with a short code. 3d6 + 2 means “roll three six-sided dice, add them up and add 2.” The number before the d is how many dice, the number after it is how many sides each die has, and anything after a plus or minus sign is the modifier. This roller builds the notation for you as you change the settings, so you can match exactly what your rulebook or character sheet says.
The standard polyhedral set
| Die | Shape | Range | Average | Common uses |
|---|---|---|---|---|
| d4 | Tetrahedron | 1–4 | 2.5 | Small weapons, minor healing |
| d6 | Cube | 1–6 | 3.5 | Board games, ability scores, damage |
| d8 | Octahedron | 1–8 | 4.5 | Weapon damage, hit dice |
| d10 | Pentagonal trapezohedron | 1–10 | 5.5 | Damage, percentile pairs |
| d12 | Dodecahedron | 1–12 | 6.5 | Heavy weapons, hit dice |
| d20 | Icosahedron | 1–20 | 10.5 | Attack rolls, skill checks, saving throws |
| d100 | Percentile | 1–100 | 50.5 | Random tables, percentage chances |
How the odds work
A single die is uniform: every face has the same chance, so a d20 rolls a 20 exactly 5% of the time. Adding dice together changes the shape of the results. Two d6 can total anywhere from 2 to 12, but 7 is the most likely total because six combinations make it (1+6, 2+5, 3+4, 4+3, 5+2, 6+1) out of 36, a chance of 1 in 6. Totals of 2 and 12 have only one combination each, 1 in 36. The more dice you add, the more the results cluster around the average, which is why 3d6 produces far fewer extreme scores than 1d20 even though their ranges are similar.
The average of a roll is easy to work out: each die averages (sides + 1) ÷ 2, so 4d8 + 3 averages 4 × 4.5 + 3 = 21. The tool shows the lowest, highest and average result for whatever you have set up, which is handy for balancing encounters or comparing weapons.
Fair rolls every time
Physical dice can be slightly unbalanced by manufacturing flaws, rounded edges or air bubbles in the plastic. This roller uses crypto.getRandomValues with rejection sampling, so each face of each die has exactly the same probability and no roll affects the next. On a single d20 the tool also calls out a natural 20 or natural 1, since many games treat those as critical results.
Tips for game night
- Keep the tab open on a phone or tablet in the middle of the table, and press R or tap the tray to roll.
- Use the history table to settle “what did I roll?” questions.
- For a percentile roll, choose d100 rather than two d10s.
- For a quick yes-or-no decision, the Coin Flip is faster; for picking between named options, try Spin the Wheel.
Frequently asked questions
Are these dice rolls random?
Yes. Each die uses your browser’s cryptographically secure random generator with rejection sampling, so every face is equally likely and rolls are independent of each other.
What does 2d6 + 3 mean?
Roll two six-sided dice, add the two results together, then add 3. Set Number of dice to 2, choose d6 and set the modifier to 3 to roll it here.
Can I roll different types of dice at once?
Each roll uses one die type. For mixed rolls such as 1d8 + 1d6, roll each part separately and add the totals, or use the history table to keep track.
Why does 7 come up so often with two dice?
More combinations add up to 7 than to any other total: six of the 36 possible outcomes. That gives 7 a one-in-six chance, while 2 and 12 each have a one-in-36 chance.