What dice types are supported?

The calculator supports d4, d6, d8, d10, d12, and d20 — all standard polyhedral dice used in tabletop RPGs and board games.

How is the probability computed?

The tool enumerates all possible combinations of dice faces and counts how many produce the target outcome. The probability equals that count divided by the total number of outcomes (faces^dice).

Why does the distribution look like a bell curve?

When rolling multiple dice, middle totals appear far more often than extreme values because there are many combinations that produce them. Rolling 2d6, for example, gives a 7 on 6 out of 36 combinations but gives a 2 on only 1 out of 36.

What is the maximum number of dice I can calculate?

Up to 10 dice are supported. Beyond that the number of combinations grows very large and the browser would slow down noticeably.

Can I calculate at-least or at-most probabilities?

Yes. Use the "At least" or "At most" fields to find the cumulative probability of rolling a sum greater than or equal to, or less than or equal to, your chosen target.

Does this model advantage, rerolls or exploding dice?

No. Results cover the sum of independent fair dice of one selected face count. Advantage, disadvantage, weighted dice, rerolls, exploding dice and keep-highest rules need different distributions.

Dice Probability Calculator

Choose d4, d6, d8, d10, d12 or d20 and calculate exact-sum, at-least, at-most and inclusive-range probabilities from the full distribution.

Dice Configuration

Dice Type

Number of Dice 2

1510

Target Outcome

Exact Sum

At Least

At Most

Min Roll

—

Max Roll

—

Average

—

Total Outcomes

—

Probability Distribution

Press "Calculate Probability" to see the distribution.

All Outcomes

Sum	Ways	Probability	Cumulative

Summary

Choose d4, d6, d8, d10, d12 or d20 and calculate exact-sum, at-least, at-most and inclusive-range probabilities from the full distribution.

How it works

Choose the dice type (d4, d6, d8, d10, d12, or d20) from the dropdown.
Set the number of dice to roll (1 to 10).
Enter an exact sum, lower bound, upper bound, or both bounds for an inclusive range.
The calculator enumerates all possible outcomes and computes exact probabilities.
View the full probability distribution chart to see the bell curve for your dice set.

Use cases

Calculate the odds of rolling a critical hit in Dungeons and Dragons.
Determine the chance of a specific total in tabletop RPG combat.
Analyze board game dice fairness and outcome distributions.
Teach students probability concepts with tangible, relatable examples.
Compare attack strategies by evaluating probability of success.
Find the most likely roll total for any dice combination.
Verify whether a game mechanic is balanced before publishing.
Plan risk-based decisions in wargames or strategy board games.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu