How to Roll Dice Online — Free Dice Roller (2026)

Tabletop roleplaying games, board games, and probability exercises all rely on dice — but not everyone has a full polyhedral set on hand, and physical dice can roll off the table, get lost, or be impractical during remote play. brevio Dice Roller supports every standard die type from d4 to d20, lets you roll multiple dice simultaneously, and generates results using the browser's cryptographic random number generator. Everything runs client-side — no server, no account, no ads interrupting your session.

How to Use the Dice Roller

1. Open brevio Dice Roller.
2. Select the die type: d4, d6, d8, d10, d12, d20, or d100 (percentile).
3. Choose how many dice to roll (1–20 dice at once).
4. Click "Roll". Results appear instantly with individual values and a sum.
5. Click again to roll again. Each roll is fully independent.
6. Use the roll history panel to review previous results in the same session.

The Standard Polyhedral Dice: What Each One Is For

The seven standard polyhedral dice originated in the 1970s with the publication of Dungeons & Dragons. Each die type has a distinct shape and a set of primary uses in tabletop RPGs and wargames.

Probability of Outcomes on Each Die

Every face on a fair die has an equal probability of 1/n, where n is the number of faces. On a d20, each number from 1 to 20 has a 5% probability. On a d6, each number from 1 to 6 has a 16.7% probability. This uniform distribution is what makes standard dice useful for randomized game mechanics — every outcome is equally likely.

When you roll multiple dice and sum them, the distribution changes. Rolling 2d6 (two six-sided dice) produces a bell-curve distribution centered on 7, because there are 6 ways to roll a 7 but only 1 way to roll a 2 or 12. This is why games that use dice pools (multiple dice summed) produce more predictable average outcomes than single-die rolls — extreme results become exponentially rarer with each additional die.

Critical Hits and the d20

In D&D 5e, a natural 20 on an attack roll is a critical hit. The probability of rolling a natural 20 on a d20 is exactly 5% (1 in 20). With Advantage (rolling two d20s and taking the higher), the probability of at least one natural 20 rises to 9.75% — almost double. With Disadvantage (taking the lower), it drops to 0.25%.

Rolling Multiple Dice: Common Notation

Standard dice notation uses the format XdY where X is the number of dice and Y is the number of faces. For example:

• 3d6 — roll three six-sided dice and sum them (used for D&D ability score generation)
• 2d8+5 — roll two d8s, sum them, add 5 (a common damage roll with a modifier)
• 1d20+3 — roll one d20 and add 3 (an attack or skill check with a +3 proficiency or ability modifier)
• 4d6 drop lowest — roll four d6s and discard the lowest result (the standard D&D character creation method)

The brevio roller shows the individual results of each die before summing, so you can apply any drop-lowest or drop-highest rules manually.

Use Cases Beyond Tabletop RPGs

Board and Card Games

Classics like Monopoly, Yahtzee, Risk, and Catan use standard d6s. The digital roller is useful when physical dice are missing, damaged, or when playing a print-and-play game that requires specific die types not in a standard set.

Teaching Probability

Rolling hundreds of dice quickly and observing the frequency distribution is a practical way to demonstrate the law of large numbers and the difference between uniform distributions (single die) and normal-ish distributions (multiple dice summed). The roll history panel makes it easy to collect data across many rolls.

Random Selection

A d6 can select among six options, a d10 among ten. Assigning options to numbers and rolling is faster than writing slips of paper or using a picker tool when the number of choices fits a standard die.

FAQ

Is the roller fair?

Yes. Each die roll uses crypto.getRandomValues(), the browser's CSPRNG, seeded from hardware entropy. The output is uniformly distributed — every face has exactly the same probability. Physical dice can have manufacturing imperfections that introduce small biases; the digital roller has none.

Can I roll more than 20 dice at once?

The default maximum is 20 dice per roll, which covers all standard game scenarios including large fireball damage rolls (8d6) and high-level sneak attack (12d6 or more at level 20). If your game requires more, roll in two batches and sum the results.

Does the tool save my roll history?

Roll history is kept in the current browser session only (in memory). Closing the tab clears it. No roll data is stored in localStorage, sent to a server, or persisted between sessions. This is by design — your game session data stays private.