D&D Dice Roller Calculator

Your details

Single roll: choose die + count. Ability score: 4d6 drop lowest for one score. Full set: six ability scores at once.
How many dice of the selected type to roll at once.
The type of polyhedral die. d20 is the signature D&D die.
Flat bonus or penalty added to the total (e.g. +5 from a proficiency bonus).
Advantage: roll two d20s and keep the higher. Disadvantage: keep the lower. Only applies to d20 rolls.
The number you need to meet or beat for a success. Leave at 0 to skip the probability check.
Expected averageUnlikely success
10.5

The mean result you can expect over many rolls

Minimum possible1
Maximum possible20
Probability of hitting DC30%
Advantage average13.67
Disadvantage average7.33
30%
Very unlikely<25%Unlikely25%-50%Even odds50%-75%Likely75%+
Minimum1
Average10.5
Maximum20

Expected roll: 10.5 (d20)

  • Rolling 1d20 averages 10.5, with results from 1 to 20.
  • You have a 30.0% chance of meeting or beating DC 15.
  • With advantage your d20 averages 13.67, with disadvantage it averages 7.33: a swing of about 6.33 points.
  • A natural 20 (crit) has a 5% chance per normal roll, rising to about 9.75% with advantage and falling to 0.25% with disadvantage.

Next stepUse the Advantage or Disadvantage mode to see exactly how Inspiration or Frightened shifts your odds.

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