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Dice Probability Calculator

Calculates the probability of any total on any number of dice, with the complete distribution counted rather than estimated.

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In short Rolling 7 on two six-sided dice has a probability of 16.6667% — 6 of the 36 possible outcomes. It is the most likely total, and the reason is pure counting: 7 is the only sum that every face can contribute to, from 1+6 through to 6+1. There is exactly one way to roll 2 and one way to roll 12, which is why the extremes are rare and the middle is common. That is where the bell shape comes from, and it appears from nothing but enumeration. This page builds the complete distribution by convolution rather than simulating rolls, so every figure is an exact count of whole outcomes. Two dice give 36 outcomes, three give 216, and ten six-sided dice give over 60 million — all counted exactly, which is why the answers are precise rather than approximate. The important thing this makes visible is that sums are NOT equally likely, even though each individual face is. People reason about the total as though it behaves like a single die, and it does not: on 3d6 the middle totals of 10 and 11 have 27 ways each while 3 and 18 have one apiece, a 27-fold difference. The dice are assumed fair and independent, which is the only assumption on the page.

How to use the Dice Probability Calculator

  1. Enter your figures in the input fields.
  2. The result updates as you type, together with the full working.
  3. Check the breakdown table to see exactly how the number was reached.

About the Dice Probability Calculator

The exact probability of any dice total, from the complete counted distribution.

What people use it for

  • Working out odds in a board or role-playing game.
  • Probability homework on dice.
  • Seeing why some totals are far more common than others.

Details

Ways to roll 7 on two dice6 of 36
Ways to roll 2 or 121 each
Total outcomes on three dice216
Most likely totals on 3d610 and 11, with 27 ways each
P(10 or more on 2d6)16.6667%

The maths behind it

This tool uses The distribution of a sum of dice is the repeated convolution of one die, and the probability is favourable outcomes ÷ sⁿ. Every intermediate value is shown on screen, so the result can be checked by hand.

The table is the entire distribution, not a sample of it — every possible total with the exact number of ways to make it.

Where this tool stops

Fair, independent dice. Loaded dice, dice that touch, and any system that rerolls or drops the lowest are outside this — the last is common in role-playing games and changes the distribution substantially.

Frequently asked questions

Why is 7 the most common roll on two dice?
Because it is the only total every face can be part of — 1+6, 2+5, 3+4 and their reverses give six combinations, more than any other sum. It is a counting fact, not a property of the dice.
Are all totals equally likely?
No, and this is the most common mistake. Each FACE is equally likely; the totals are not, because there are many ways to make a middling sum and only one way to make each extreme.
Is this simulated?
No. The complete distribution is counted by convolution, so the numbers are exact whole-outcome counts rather than estimates from repeated trials.
What about rolling at least one specific number?
That is a different question and often easier through the complement: the chance of at least one 6 in four rolls is 1 − (5/6)⁴ = 51.77%. The binomial page handles that form directly.
Are there any usage caps on the Dice Probability Calculator?
There is no cost and no cap. The Dice Probability Calculator is not a demo of a paid product, so nothing is held back or watermarked.
Does anything I enter leave my computer?
No. The Dice Probability Calculator runs entirely in your browser using JavaScript. Because the work happens locally, the page also keeps working if your connection drops, and closing the tab is all it takes to discard everything.
What formula does the Dice Probability Calculator use?
It uses The distribution of a sum of dice is the repeated convolution of one die, and the probability is favourable outcomes ÷ sⁿ. The full working is printed under the result, so you can follow every step rather than trusting a black box.
Give me a worked example.
Enter 2 six-sided dice, exactly 7 and the Dice Probability Calculator returns 16.6667% (6 of 36).
Who is the Dice Probability Calculator for?
Typical uses: working out odds in a board or role-playing game. Probability homework on dice. Seeing why some totals are far more common than others. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Where does the Dice Probability Calculator stop being reliable?
Fair, independent dice. Loaded dice, dice that touch, and any system that rerolls or drops the lowest are outside this — the last is common in role-playing games and changes the distribution substantially. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What are the key numbers for the Dice Probability Calculator?
Ways to roll 7 on two dice is 6 of 36. Ways to roll 2 or 12 is 1 each. Total outcomes on three dice is 216. These are printed on the page itself, so you do not have to take them on trust.
Is the number rounded?
The calculation runs in double precision and the result is shown to ten significant figures, so converting a value and converting it back returns the original. What is displayed is rounded for readability; what is copied is not.

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