数学

Probability Calculator

Calculate the probability of single and multiple events, including intersections and unions.

Event A

OR enter P(A) directly:

Event B

OR enter P(B) directly:
Event Decimal Percentage Fraction
P(A) Probability of A — — —
P(B) Probability of B — — —
P(A') Probability of NOT A — — —
P(A ∩ B) Both A and B (Independent) — — —
P(A ∪ B) Either A or B (Non-mutually excl.) — — —
P(A ∪ B) Either A or B (Mutually exclusive) — — —
使い方
  1. Enter the number of favorable outcomes and total possible outcomes for Event A (e.g., rolling a 4 on a 6-sided die: 1 favorable, 6 total).
  2. Alternatively, you can enter the decimal probability directly (e.g., 0.1667).
  3. Do the same for Event B.
  4. The calculator instantly provides the probabilities for each event occurring, not occurring, both occurring together (assuming independence), or either occurring.

計算式

P(A) = Favorable / Total

Not A (Complement): P(A') = 1 - P(A)

Intersection (Independent): P(A ∩ B) = P(A) × P(B)

Union (Non-Mutually Exclusive): P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

Union (Mutually Exclusive): P(A ∪ B) = P(A) + P(B)

The Probability Calculator makes it simple to compute complex statistical likelihoods. Whether you are calculating the odds of a coin flip, the chance of pulling a specific card from a deck, or combining multiple independent statistical events, this tool breaks down the math into decimals, fractions, and percentages.