Probability Calculator
A simple tool for two event probability. Enter P(A) and P(B), then choose a mode: Independent, Non‑independent with P(A ∩ B), or Conditional. The calculator computes the union, intersection, complements, “A only”, “B only”, and “neither”.
Calculation Mode
Choose how to determine the intersection. Both P(A) and P(B) are always required.
0–1 or %
Enter the probability of event A. Accepts decimal 0–1 or percentage (e.g., 30 or 30%).
0–1 or %
Enter the probability of event B. Accepts decimal 0–1 or percentage (e.g., 50 or 50%).
Independent mode uses P(A ∩ B) = P(A) × P(B). Non‑independent mode lets you set P(A ∩ B) directly.
Conditional mode uses P(A|B) with P(B) or P(B|A) with P(A) to determine the intersection.