Question 1

What is a D20 die?

Accepted Answer

A D20 (icosahedron) is a 20-sided die numbered 1-20, and it's the signature die of Dungeons & Dragons. It's used for nearly every core resolution in the game — attack rolls, saving throws, and ability checks — because a flat 1-20 range gives a clean 5% probability per face, making it easy to design difficulty checks around.

Question 2

What does 2d6 mean in dice notation?

Accepted Answer

2d6 means "roll two six-sided dice and add the results together." The number before the d is how many dice you roll, and the number after is how many sides each die has. So 2d6 produces a total between 2 and 12, with 7 being the most statistically likely result since there are more ways to combine two dice into a 7 than any other sum.

Question 3

What dice types are used in D&D?

Accepted Answer

Dungeons & Dragons uses seven standard polyhedral dice: D4, D6, D8, D10, D12, D20, and D100 (percentile, made from two D10s — one reads tens, one reads ones). Each is tied to different mechanics: D20 for rolls and checks, D4-D12 mostly for weapon and spell damage, and D100 for percentile-based tables and effects.

Question 4

Are virtual dice truly random?

Accepted Answer

This roller uses your browser's Math.random() function, which is a pseudorandom number generator — statistically uniform and unpredictable enough for gaming purposes, though not cryptographically secure. For casual tabletop play, virtual dice like this are every bit as fair as physical dice, without any risk of a die landing on an edge or rolling off the table.

Question 5

What is the average roll for each die?

Accepted Answer

The average of any die is (1 + number of sides) ÷ 2. So a D4 averages 2.5, a D6 averages 3.5, a D8 averages 4.5, a D10 averages 5.5, a D12 averages 6.5, a D20 averages 10.5, and a D100 averages 50.5. These averages are useful for quickly estimating expected damage output over many rolls.

Question 6

What is a critical hit in D&D?

Accepted Answer

A critical hit happens when you roll a natural 20 (the die itself, before any modifiers) on an attack roll. It automatically hits regardless of the target's armor class, and you roll extra damage dice as a bonus. A natural 1 on an attack roll is the opposite — an automatic miss, sometimes called a critical failure or "fumble."

Question 7

How do I roll D&D character stats?

Accepted Answer

The most common method is "4d6 drop lowest": roll four six-sided dice, discard the lowest result, and sum the remaining three. Repeat this six times to generate your six ability scores (Strength, Dexterity, Constitution, Intelligence, Wisdom, Charisma). Set this roller to D6 with a count of 4, roll, and manually drop your lowest die each time.

Question 8

What is the probability of rolling a specific number?

Accepted Answer

For a single die, every face has an equal 1-in-(number of sides) chance — a D20 gives each number exactly a 5% chance. For multiple dice added together, the middle values become more likely because there are more combinations that produce them — for example, rolling a 7 on 2d6 has a 16.7% chance (6 out of 36 combinations), far more likely than rolling a 2 or a 12 (each just 2.8%).

Question 9

Can I use a keyboard shortcut to roll dice?

Accepted Answer

Yes — press the Spacebar anywhere on this page (as long as you're not typing in the notation box) to instantly reroll with your current dice settings. It's a fast way to roll repeatedly during a game session without reaching for your mouse each time.

Question 10

What is a D100 percentile die?

Accepted Answer

A D100 (percentile die) produces a number from 1 to 100 and is traditionally rolled as two D10s — one designated as the "tens" die and one as the "ones" die. It's used for percentage-based tables, like random loot generation or wild magic surge effects, where you need a fine-grained 1-in-100 outcome.

Die	Average	Min	Max	P(max)	P(≥half)	Common Uses
D4	2.5	1	4	25.0%	50%	Dagger, small spells
D6	3.5	1	6	16.7%	50%	Short sword, fireball dice
D8	4.5	1	8	12.5%	50%	Longsword, healing spells
D10	5.5	1	10	10.0%	50%	Heavy weapons, hit die
D12	6.5	1	12	8.3%	50%	Greataxe, Barbarian HD
D20	10.5	1	20	5.0%	50%	Attack rolls, saving throws
2d6	7	2	12	2.78%	58.3%	Greatsword, stat rolls
D100	50.5	1	100	1.0%	50%	Percentile checks, wild magic

Virtual Dice Roller

All 7 RPG Dice Explained

D4 — Tetrahedron

D6 — Cube

D8 — Octahedron

D10 — Pentagonal Trapezohedron

D12 — Dodecahedron

D20 — Icosahedron

Dice Statistics & Probability

Rolling D&D Character Stats — The 4d6 Drop Lowest Method

| Dice Notation & Probability Formulas

Standard Dice Notation

Probability of a Specific Roll

D&D Advantage and Disadvantage

Frequently Asked Questions

Related Calculators