How to use this calculator
- Enter or choose number of dice.
- Enter or choose sides per die.
- Enter or choose modifier (added to the total).
- The total updates as you type. Use Copy result or Share to keep it.
Method
Total = sum of rolls + modifier; Average = dice × (sides + 1) ÷ 2 + modifier; Range = dice + modifier to dice × sides + modifier
- dice
- number of dice
- sides
- faces on each die
Worked example
- Each d6 averages (1 + 6) ÷ 2 = 3.5.
- Three dice average 3 × 3.5 = 10.5.
- The total ranges from 3 (all ones) to 18 (all sixes).
3d6 gives a total from 3 to 18, averaging 10.5; each roll is random.
What the result means
With several dice, middle totals are far more common than extremes: 3d6 gives 10 or 11 a quarter of the time but 3 or 18 less than 1% of the time.
Assumptions and limits
- Fair dice: every face equally likely, using crypto.getRandomValues with rejection sampling to avoid bias.
- Special rules such as exploding dice, advantage or dropping the lowest die are not applied.
Questions
Is this as fair as a real die?
Fairer than most. The browser’s cryptographic generator has no physical bias, and the conversion to faces avoids the small bias a naive modulo would add.
What does 2d6 + 3 mean?
Roll two six-sided dice, add them, then add 3: totals from 5 to 15.