Omni Calculator logo

D20 Dice Roller Calculator

Created by Joanna Śmietańska, PhD
Reviewed by Komal Rafay
Last updated: Jan 18, 2024

The D20 dice roller calculator is easy to use online D20 roller for tabletop gaming. Roll up to 15 D20 dice at one time.

Just select the number of the 20-sided dice and press the "ROLL" button, and it will start rolling and land on a random number from 1 to 20. Roll your D20 die now!

D20 dice: A 20 sided die

The D20 die is a 20-sided signature die of the D&D (Dungeons and Dragons) game. It is the most commonly used dice in the game, which determines all strategies and attacks used during the game by players. If you're wondering what shape the D20 is, then it's called an icosahedron - a polyhedron with 20 faces. Each face of the 20-sided die is marked 1–20.

D20 rolls further than other dice because it is the most spherical. First, you roll D20, the "deciding" dice in D&D, to see if you hit the enemy. Each value has a 5% chance. Then you roll other dice to see how much damage you'll deal.

How to use this D20 dice roller calculator?

Using our 20-sided dice roller is super easy:

  1. Select the number of D20 dice you want to throw, any number from one to 15.

  2. Go to the bottom of the D20 roller, click on "Select", then click "Roll". To roll the dice again, click on "Roll" and select "Roll" a second time. Happy rolling!

  3. The D20 dice roller calculator shows you the sum of the values of the rolled dice at the bottom. Underneath the total, our 20-sided dice roller shows the result of each die.

  4. Click the "Roll" button to throw a die again. You can change the number of them at will.


What is D20 in gaming and RPGs?

The D20 is a slang term for a 20-sided fair die. This icosahedral-shaped die is mainly associated with Dungeons and Dragons (DnD), but it is also used in many other tabletop and online games. Each roll shows a number from 1 to 20. Players occasionally roll a D20 to determine if they have successfully completed the task.

How do D20 rolls work in Dungeons and Dragons?

  1. Start with a base number (e.g., your opponent's armor class) and that is the number you need to defeat.
  2. Roll a D20 die.
  3. Add any bonuses you have that apply to that roll.
  4. If you throw more, you succeed.
  5. Note that 20 means the absolute success of your action and 1 means total failure.

Is a D20 a dodecahedron?

No, the D20 die is an icosahedron, with 20 faces and 12 vertices. A D12 die is a dodecahedron, it has 12 faces and 20 vertices.

Joanna Śmietańska, PhD
Number of dice
Let 'em roll!
Click Select/Roll, click Roll 🎲
Check out 33 similar probability theory and odds calculators 🎲
AccuracyBayes theoremBertrand's box paradox… 30 more
People also viewed…

Binomial distribution

Use the binomial distribution calculator to calculate the probability of a certain number of successes in a sequence of experiments.


Do you feel like you could be doing something more productive or educational while on a bus? Or while cleaning the house? Well, why don't you dive into the rich world of podcasts! With this podcast calculator, we'll work out just how many great interviews or fascinating stories you can go through by reclaiming your 'dead time'!

Sample size

The sample size calculator determines the sample size required for the result to be statistically significant.

Secretary problem (Valentine's day)

Use the dating theory calculator to enhance your chances of picking the best lifetime partner.
Copyright by Omni Calculator sp. z o.o.
Privacy, Cookies & Terms of Service