Probability Calculator
Calculate probabilities for various scenarios with visual representations
Calculation Type
Visual Representation
Probability Distribution
How Probability Works
Probability measures the likelihood of an event occurring, expressed as a number between 0 and 1. Enter values to see calculations and visualizations.
Probability Facts
- • The probability of an impossible event is 0
- • The probability of a certain event is 1
- • The sum of all probabilities in a sample space is 1
- • For independent events, P(A and B) = P(A) × P(B)
Understanding Probability
What is Probability?
Probability is the branch of mathematics concerning numerical descriptions of how likely an event is to occur, or how likely it is that a proposition is true.
The probability of an event is a number between 0 and 1, where 0 indicates impossibility and 1 indicates certainty.
Common Probability Formulas
- Single Event: P(A) = Number of favorable outcomes / Total outcomes
- AND Rule: P(A ∩ B) = P(A) × P(B) [if independent]
- OR Rule: P(A ∪ B) = P(A) + P(B) – P(A ∩ B)
- Conditional: P(A|B) = P(A ∩ B) / P(B)
- Binomial: P(k successes) = C(n,k) × p^k × (1-p)^(n-k)