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Dice Roller

Understanding Dice & Dice Notation

Dice are the heart of tabletop gaming, introducing randomness and unpredictability to games like Dungeons & Dragons, Pathfinder, and board games. Different-sided dice (polyhedral dice) are used for different purposes.

Common Dice Types

  • d4 (4-sided): Pyramid shape, used for small damage (daggers, minor spells)
  • d6 (6-sided): Standard cube, most common dice (used in almost every game)
  • d8 (8-sided): Octahedron, medium weapons (longsword, crossbow)
  • d10 (10-sided): Pentagonal trapezohedron, percentile rolls (combine two d10 for d100)
  • d12 (12-sided): Dodecahedron, heavy weapons (greataxe)
  • d20 (20-sided): Icosahedron, THE iconic D&D die for skill checks, attacks, and saves

Dice Notation (XdY+Z)

Dice notation is a shorthand used in tabletop RPGs. The format is XdY+Z:

  • X = Number of dice to roll
  • d = "dice" (separator)
  • Y = Number of sides on each die
  • +Z = Modifier to add (optional)

2d6 = Roll two 6-sided dice, add them together
1d20+5 = Roll one 20-sided die, add 5
3d8-2 = Roll three 8-sided dice, subtract 2

💡 Expert Tip: Advantage & Disadvantage in D&D 5e

In D&D 5th Edition, "Advantage" means roll 2d20 and take the higher result. "Disadvantage" means roll 2d20 and take the lower. Mathematically, advantage increases your average roll from 10.5 to 13.8—a huge boost. Never underestimate positional tactics that grant advantage!

⚠️ Common Mistake: Misunderstanding Probability

Many players think that rolling a 10 on a d20 is "average," but it's not—the average is 10.5 (the middle value). Also, remember that each roll is independent: if you roll three 1s in a row, you're NOT "due" for a 20. This is called the "Gambler's Fallacy." Every d20 roll has exactly a 5% chance of being a 20, no matter what came before.

Reviewed by: James Rodriguez, Game Master & RPG Enthusiast
Last updated: November 27, 2025

Frequently Asked Questions

What are the different types of dice?

Common types include d4, d6, d8, d10, d12, and d20. D&D uses all of these, with d20 being the most iconic for skill checks and attacks.

How do you roll dice for D&D?

D&D uses dice notation like "2d6" (roll two 6-sided dice) or "1d20+5" (roll one 20-sided die and add 5). Attack rolls use 1d20, while damage often uses combinations like 2d6 or 1d8.

What is the probability of rolling a 20 on a d20?

The probability is 1/20 or 5%. This is called a "natural 20" or "critical hit" in D&D. Rolling a 1 also has a 5% probability.

Why use a virtual dice roller?

Virtual dice rollers are perfect when you don't have physical dice, play online (Roll20), need many dice quickly, or want truly random results without bias from worn dice.