🎲Probability Calculator

Calculate basic, compound, and conditional probability for events.

Enter probabilities as decimals (0 to 1) or percentages.

P(A)

About Probability Calculator

Calculate basic event probability, complement probability, union (A or B), intersection (A and B), and conditional probability P(A|B). Supports independent and mutually exclusive events, and includes a built-in dice, coin, and card probability reference.

How to Use Probability Calculator

1
Choose the calculation type
Select from basic probability, complement, union, intersection, or conditional probability.
2
Enter the probabilities
Input the event probability values as fractions, decimals, or percentages.
3
Calculate and interpret
View the result with a plain-English explanation of what the probability means.

Common Use Cases

Solving probability problems in maths and statistics courses
Analysing risk and likelihood in decision making
Understanding card game and dice odds
Calculating compound event probabilities in data science

Frequently Asked Questions

What types of probability can I calculate?

Single event probability (P(A) = favourable/total), complement (P(not A)), union (P(A∪B) for independent and mutually exclusive events), intersection (P(A∩B)), and conditional probability P(A|B) = P(A∩B)/P(B).

What is the difference between mutually exclusive and independent events?

Mutually exclusive events cannot both occur at the same time (P(A∩B) = 0). Independent events do not affect each other's probability (P(A∩B) = P(A) × P(B)).