How to use the dice roller
- Pick a Die type: D4, D6, D8, D10, D12, D20 or D100. Choose Custom for any die from 2 to 1,000 sides.
- Set Number of dice (1 to 100) and a whole-number Modifier such as 3 or -2, which is added once to the total.
- Choose a Roll mode. Normal adds the dice. Advantage rolls the whole pool twice and keeps the higher total, Disadvantage keeps the lower, and Drop lowest removes the smallest die before adding.
- Press Roll or the Space bar. The big number is the total and the line under it lists every die. Dropped dice are struck through.
- The DnD quick rolls buttons fill in the fields and roll. Roll history keeps your last 30 rolls until you refresh.
How each die is rolled
For every die the tool asks your browser for a 32-bit number from crypto.getRandomValues(), the cryptographic generator described by MDN. A plain remainder would make low faces very slightly likelier, so values above the largest exact multiple of the die size are drawn again, the standard fix for modulo bias. The remainder plus 1 is the face. Notation follows dice notation: 2D6+3 is two six-sided dice added together plus 3. Advantage and disadvantage follow the D&D Beyond Basic Rules (roll a second d20, keep the higher or lower), and drop lowest matches their ability score method: roll four six-sided dice and total the highest three.
Worked example with the default settings
The defaults are D6, 1 die, modifier 0 and Normal mode, and the page rolls once on load. You see a line such as "1D6: 4 = 4" with "Possible totals: 1 to 6 (average 3.5)" under it. Press the Damage (2D6+3) quick roll and you get something like "2D6+3: 4 + 5 + 3 = 12" with "Possible totals: 5 to 15 (average 10)". Two dice add up to 2 through 12, and 7 is the most common sum (6 of 36 combinations, 16.7 percent), so 10 is the most likely damage.
Limits and edge cases
- A D10 here shows 1 to 10, as a physical D10 marked 0 to 9 reads 0 as 10. D100 is one roll from 1 to 100, not two D10s.
- Only whole numbers work. 0 dice, 101 dice or a modifier of 2.5 shows a message instead of rolling.
- A negative modifier can push the total below 1 (1D4-10 can give -8). The tool does not round up.
- The 5e rules apply advantage to a d20. With more dice the tool rolls the whole pool twice. Drop lowest needs at least 2 dice.
- Past 20 dice the breakdown shows the sum, not every die. This is for games and classrooms, not regulated gambling.
Need a yes or no? Use the coin flip. To pick from a list, try spin the wheel. For exact odds, use the probability calculator.
Dice roller FAQ
Are the dice rolls really random?
Yes. Each die uses your browser's cryptographic random generator, and any value that would favor a low face is redrawn, so every face has exactly the same chance. The roll happens in your browser and is not stored on a server.
How does advantage work in D&D, and how much does it help?
You roll two d20 and keep the higher one. The average d20 result goes from 10.5 to 13.8, and the chance of at least one natural 20 rises from 5 percent to 9.75 percent. Disadvantage keeps the lower die and drops the average to 7.2.
What does 4D6 drop lowest mean?
Roll four six-sided dice, ignore the lowest one and add the other three. It is the standard way to generate a D&D ability score, and the average is about 12.2 compared with 10.5 for plain 3D6. Use the Ability quick roll, or set Number of dice to 4 and Roll mode to Drop lowest.
Can I roll a D3, D5 or D30?
Yes. Choose Custom in Die type and type the number of sides, anywhere from 2 to 1,000.
Sources: MDN Web Docs, Wikipedia, D&D Beyond Basic Rules.