D20 Dice Roller Calculator
Perfect for tabletop RPGs. Roll any number of d20 dice, inspect outcomes, and observe roll distributions.
Results: 16, 4, 9, 19, 1, 1, 3, 13, 18, 14, 16, 15, 15, 4, 9, 9, 1, 20, 3, 4
Total: 194
Average: 9.70
Highest: 20
Lowest: 1
| Face | Count | Relative frequency |
|---|---|---|
| 1 | 3 | 0.150 |
| 2 | 0 | 0.000 |
| 3 | 2 | 0.100 |
| 4 | 3 | 0.150 |
| 5 | 0 | 0.000 |
| 6 | 0 | 0.000 |
| 7 | 0 | 0.000 |
| 8 | 0 | 0.000 |
| 9 | 3 | 0.150 |
| 10 | 0 | 0.000 |
| 11 | 0 | 0.000 |
| 12 | 0 | 0.000 |
| 13 | 1 | 0.050 |
| 14 | 1 | 0.050 |
| 15 | 2 | 0.100 |
| 16 | 2 | 0.100 |
| 17 | 0 | 0.000 |
| 18 | 1 | 0.050 |
| 19 | 1 | 0.050 |
| 20 | 1 | 0.050 |
How to Use This Calculator
- Enter the number of 20-sided dice to roll.
- Click the roll button to generate fresh random outcomes.
- Inspect total, average, highest, and lowest rolls to assess luck or expected values.
- Use frequency counts to study roll distributions over repeated trials.
Formula
Each d20 outcome is uniform on {1, 2, ..., 20}
Expected value per die = (1 + 20) / 2 = 10.5
Variance per die = (20² − 1) / 12 ≈ 33.25
Total expected value for n dice = 10.5 × n
Full Description
D20 dice are central to many role-playing game mechanics. This tool simulates fair d20 rolls and surfaces descriptive statistics, helping players and game masters assess probabilities or track outcomes.
Frequently Asked Questions
Does this support advantage/disadvantage mechanics?
Not directly. Roll two sets manually and apply your rule for advantage or disadvantage.
Can I roll a single die?
Yes. Set the number of dice to 1 for individual d20 rolls.
Are results independent?
Each roll uses a new random value; all outcomes are independent.
Why track frequency?
Frequency tables reveal how evenly outcomes are distributed and can be useful for probability demonstrations.