What is the average roll on each die type?

Average roll values: D4 = 2.5, D6 = 3.5, D8 = 4.5, D10 = 5.5, D12 = 6.5, D20 = 10.5. The average of any die is (1 + max) ÷ 2, since all values are equally probable.

What is a critical hit and critical fail on a D20?

In Dungeons & Dragons and similar games, rolling a 20 on a D20 is a 'natural 20' or critical hit — the best possible outcome. Rolling a 1 is a 'natural 1' or critical failure — the worst possible outcome. Each has a 5% probability per roll (1 in 20).

Dice Roller Online - D4 D6 D8 D10 D12 D20

Q: What do D4, D6, D8, D10, D12, D20 mean?

The 'D' stands for die, and the number indicates how many sides it has. D6 is a standard six-sided die. D20 is a twenty-sided die. These dice types are standard in tabletop role-playing games like Dungeons & Dragons. A D6 rolls 1–6, a D10 rolls 0–9 (or 1–10 depending on convention), a D20 rolls 1–20.

Q: How does the dice roller generate random numbers?

This tool uses crypto.getRandomValues() — a browser cryptography API — to generate random bytes. For each die, it takes a random 32-bit integer and computes (value modulo sides) + 1. This gives equal probability to each face, with no bias.

Q: Can I roll multiple dice at once?

Yes. Use the count selector to choose 1–10 dice of the same type. The roller shows each individual result and the total sum. For example, rolling 3d6 shows three individual results (like 4, 2, 6) and the sum (12).

What Is a Dice Roller?

A dice roller simulates the roll of one or more polyhedral dice. In tabletop role-playing games (RPGs) like Dungeons & Dragons, various dice types are used for different purposes — a six-sided die for damage, a twenty-sided die for attack rolls, and so on. This online dice roller supports all standard RPG dice types and uses cryptographic randomness so every roll is genuinely fair.

How to Use This Dice Roller

Select a die type (D4 through D20) by clicking the buttons at the top. Choose how many dice to roll (1–10) using the plus and minus buttons. Click ROLL or press Space/Enter. Each die's result appears in its own tile, and the total sum is shown prominently. The last 10 rolls are saved in the history below.

Dice Types Explained

Die	Sides	Range	Average	Common Use
D4	4	1–4	2.5	Damage (dagger, magic missile)
D6	6	1–6	3.5	Most common die, many board games
D8	8	1–8	4.5	Hit points (fighters, rangers)
D10	10	1–10	5.5	Percentile rolls (with two D10)
D12	12	1–12	6.5	Barbarian hit dice, great axe
D20	20	1–20	10.5	Attack rolls, saving throws (D&D)

Benefits of a Virtual Dice Roller

No physical dice needed: Roll any combination of dice from your phone or computer.
Cryptographically random: Uses crypto.getRandomValues() — impossible to predict or manipulate.
Roll history: Track the last 10 rolls to verify fairness and review recent results.
Multiple dice at once: Roll up to 10 dice simultaneously and get the sum instantly.

Frequently Asked Questions

What do D4, D6, D8, D10, D12, D20 mean?

'D' stands for die, the number is the number of sides. D6 is a standard six-sided die, D20 is a twenty-sided die. These are the standard polyhedral dice used in tabletop RPGs. A D6 rolls 1–6, a D20 rolls 1–20.

How does the dice roller generate random numbers?

It uses crypto.getRandomValues() to generate a 32-bit random integer, then computes (value % sides) + 1. This gives each face an equal probability. It is the same cryptographic randomness used for security applications.

Can I roll multiple dice at once?

Yes — set the count to 2–10 and click Roll. You'll see each die's result individually plus the total sum. For example, rolling 3d6 shows three results like 4, 2, 6 with a sum of 12.

What is the average roll on each die?

Average = (1 + sides) ÷ 2. So D4 = 2.5, D6 = 3.5, D8 = 4.5, D10 = 5.5, D12 = 6.5, D20 = 10.5. Over many rolls, results will converge toward these averages.

What is a critical hit on a D20?

In Dungeons & Dragons, rolling a 20 (natural 20) is a critical hit — maximum effect. Rolling a 1 (natural 1) is a critical failure. Each has a 5% probability per roll. The drama around these extreme results is central to D&D gameplay.