Probability Calculator

Calculate probabilities for unions, intersections, series of events, and normal distributions with our free online tool.

This tool is designed for students, statisticians, and professionals needing quick and accurate probability calculations. Compute unions, intersections, complements, and normal distribution probabilities with ease, all in your browser.

Probability Calculators

Formulas Used:

P(A ∩ B) = P(A) × P(B)

P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

P(A') = 1 - P(A)

P(B') = 1 - P(B)

P(A Δ B) = P(A ∪ B) - P(A ∩ B)

P(neither A nor B) = 1 - P(A ∪ B)

Formulas Used:

Solves for unknowns using:

P(A') = 1 - P(A)

P(B') = 1 - P(B)

P(A ∩ B) = P(A) × P(B)

P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

P(A Δ B) = P(A ∪ B) - P(A ∩ B)

Formulas Used:

Overall probability = Π(P(event) ^ repeat)

At least one failure = 1 - Overall probability

Formulas Used:

Z = (X - µ) / σ

P(Lb ≤ X ≤ Rb) = CDF(Rb) - CDF(Lb)

Confidence Intervals: ±Z * σ from mean

Formulas Used:

P(A ∩ B) = P(A) × P(B)

P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

P(A') = 1 - P(A)

P(B') = 1 - P(B)

P(A Δ B) = P(A ∪ B) - P(A ∩ B)

P(neither A nor B) = 1 - P(A ∪ B)

Formulas Used:

Solves for unknowns using:

P(A') = 1 - P(A)

P(B') = 1 - P(B)

P(A ∩ B) = P(A) × P(B)

P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

P(A Δ B) = P(A ∪ B) - P(A ∩ B)

Formulas Used:

Overall probability = Π(P(event) ^ repeat)

At least one failure = 1 - Overall probability

Formulas Used:

Z = (X - µ) / σ

P(Lb ≤ X ≤ Rb) = CDF(Rb) - CDF(Lb)

Confidence Intervals: ±Z * σ from mean

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Calculation Results

Your results will appear here after calculation

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