Dice Roller

About dice rolling

Dice are the classic randomization tool for tabletop role-playing games, board games and decision-making. The most common die is the six-sided d6, but RPG systems use many types. The d20 is central to Dungeons and Dragons, while percentile rolls use d100 (or two d10s).

This tool generates each die result using the browser's cryptographically secure random number generator, ensuring fair and unpredictable outcomes. The total is the sum of all individual die results.

How do you calculate dice roll probabilities?

To find the probability of a specific outcome, divide the number of ways it can happen by the total number of possible rolls. Example: rolling a 6 on one d6 has a 1/6 (about 16.7%) chance, since there is one favorable outcome out of six equally likely sides.

Steps to work out dice probabilities

1. Identify the die type (d4, d6, d20, etc.) and how many dice you are rolling.
2. Count the total number of possible outcomes: sides raised to the power of the number of dice, for independent rolls.
3. Count the outcomes that match what you are looking for, such as rolling a specific number or sum.
4. Divide the favorable outcomes by the total outcomes to get the probability.
5. For "at least one" questions, it is often easier to calculate the chance of it not happening and subtract from 1.

Key dice probability formulas

• sides = the number of faces on the die (6 for a standard d6, 20 for a d20)
• n = the number of dice rolled or the number of separate rolls

Example dice probabilities

Frequently asked questions

Why is a sum of 7 the most common result with two six-sided dice?

With two d6, there are 36 equally likely combinations, and 6 of them add up to 7 (1+6, 2+5, 3+4, 4+3, 5+2, 6+1) — more combinations than for any other total, which is why 7 comes up more often than 2 or 12, each of which has only 1 combination.

Does this tool use real randomness or a predictable pattern?

Each die result comes from the browser's cryptographically secure random number generator, the same category of randomness used for security-sensitive tasks, so results are not predictable or biased toward any particular face.

What is a d100 roll used for?

A d100, or percentile roll, generates a number from 1 to 100 and is common in tabletop role-playing games for chance-based checks, critical hit tables, and loot tables where a wide, granular range of outcomes is needed. It is sometimes simulated by rolling two d10s together.

How is the total calculated when rolling multiple dice?

The total is simply the sum of each individual die's result. Rolling three d6 and getting 2, 5, and 6 gives a total of 13; the distribution of totals is not flat, since middle values like 10-11 have more combinations than extreme values like 3 or 18.

These probabilities assume fair, independent dice with no bias; physical dice can have small manufacturing imperfections, but the random number generator behind this tool treats every side as equally likely.

Sources: MDN — Crypto.getRandomValues()

Privacy and safety

• Runs in your browser — Everything you type is calculated on your own device. Your inputs are never sent to a utilduck server.
• Encrypted connection — Pages are served over HTTPS, so nobody on the network can read what you load.
• Not shared with third parties — Your inputs are not passed to analytics or advertising services.
• Nothing is stored — Results are not saved to any server, and there is no account to create.

Last updated: 2026-08-17