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Dice Roller
Pick how many dice and how many sides — d4, d6, d8, d10, d12, d20, d100 or any custom die up to 100 sides — add a modifier and roll. Unlike most online dice, it also handles drop-lowest, advantage and disadvantage rolls, rolls a whole set at once, and tells you how likely the total you rolled was.
- Dice
- 2, 2
- Dice notation
- 2d6
- Every total, in order
- 4
- Chance of exactly this total
- 8.33%
- Chance of this total or higher
- 91.67%
- Average total (expected value)
- 7
- Standard deviation
- 2.42
- Most likely total
- 7
- Possible totals
- 2 to 12
- Seed for these rolls
- 2786546940
Your rolls
| Roll | Dice | Total | Chance of exactly this | Chance of this or higher |
|---|
Saved setups
Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.
Your recent calculations
Results you calculate here are kept on this device so you can come back to them.
Formula
How to use it
- Enter the number of dice and choose the sides, or Custom for any die from d2 to d100.
- Add a modifier, and choose whether to drop the lowest or highest die or keep only the highest or lowest.
- Set how many times to roll the set; every roll is listed in the table.
- Tap Roll again, or change anything, for fresh dice. Type a seed to get the same rolls every time.
Worked examples
Two six-sided dice with seed 42: 4 + 3 = 7, the most likely total (6 of the 36 combinations; 21 of 36 give 7 or more)
- You rolled
- 7
- Dice
- 4, 3
- Chance of exactly this total
- 16.67%
- Chance of this total or higher
- 58.33%
- Average total (expected value)
- 7
- Standard deviation
- 2.42
- Most likely total
- 7
- Possible totals
- 2 to 12
Six sets of 4d6, dropping the lowest die, with seed 7 (12 comes up in 167 of the 1,296 combinations)
- You rolled
- 12
- Dice
- (1), 1, 6, 5
- Every total, in order
- 12, 10, 11, 12, 12, 10
- Chance of exactly this total
- 12.89%
- Average total (expected value)
- 12.24
- Most likely total
- 13
- Possible totals
- 3 to 18
A d20 attack roll with a +3 bonus and seed 1: 13 + 3 = 16 (a 13 or better on the die is 8 faces of 20)
- You rolled
- 16
- Dice
- 13
- Dice notation
- 1d20 + 3
- Chance of exactly this total
- 5%
- Chance of this total or higher
- 40%
- Average total (expected value)
- 13.5
- Possible totals
- 4 to 23
Advantage on a d20 with a +5 bonus and seed 7: a 1 and a 2, keep the 2, total 7 (only the 1-1 pair rolls lower)
- You rolled
- 7
- Dice
- (1), 2
- Chance of exactly this total
- 0.75%
- Chance of this total or higher
- 99.75%
- Average total (expected value)
- 18.83
- Most likely total
- 25
How likely is your total?
Two six-sided dice have 36 equally likely combinations. Seven can be made six ways (1 + 6, 2 + 5, 3 + 4 and the reverses), so it comes up 1 time in 6, while 2 and 12 can each be made only one way, 1 in 36. More dice pull totals toward the middle: three dice land between 8 and 13 about two-thirds of the time (146 of 216 combinations).
A single die is flat: every face of a d20 has a 5% chance, so needing 13 or more means 8 winning faces, a 40% chance.
Drop lowest, advantage and disadvantage
Rolling 4d6 and dropping the lowest die is a common way to generate tabletop RPG ability scores. It averages 12.24 instead of 10.5 for a straight 3d6, and 13 is the single most likely result.
Advantage — rolling two d20s and keeping the higher — averages about 13.8 instead of 10.5, and disadvantage about 7.2. Advantage turns a 50% chance (11 or more) into 75%, because you only fail when both dice fail: 0.5 × 0.5 = 0.25.
Is it really random?
Each roll starts from a fresh random seed drawn by your browser and feeds it to a standard 32-bit pseudorandom generator (mulberry32), so every face is equally likely. When you type a seed, the same seed and settings always produce the same rolls — useful for sharing a roll or replaying the worked examples. Nothing you roll is sent anywhere.
Questions people ask
What is the most likely roll with 2 dice?
7. Six of the 36 combinations add up to 7, a 16.67% chance. 6 and 8 come next at 13.89% each (5 ways each).
What does 2d6 + 3 mean?
Roll two six-sided dice, add them, then add 3. The total runs from 5 to 15 and averages 10.
What is the average of 4d6 drop lowest?
12.24, compared with 10.5 for 3d6. The most likely result is 13, which comes up 172 times in 1,296 (13.3%).
How do I roll a d100?
Choose d100 (percentile) for one roll from 1 to 100, each with a 1% chance. At the table the same thing is done with two ten-sided dice, one for the tens and one for the units.