Probability Calculator
Calculate probabilities for single and multiple events, including complementary, union, and intersection probabilities.
Published by:
isCalculator Editorial Team
Reviewed by:
Review Board
Last Updated:
Was this calculator helpful?
How to use this tool?
How to Use the Probability Calculator
- Select Event Type: Choose Single Event for one event (e.g., rolling a die) or Multiple Events for two events.
- Enter Values:
- For Single Event: Input the number of favorable outcomes and total outcomes (both must be integers).
- For Multiple Events: Enter probabilities for Event A and Event B as decimals between 0 and 1 (e.g., 0.3 for 30%).
- Choose Operation (Multiple Events only): Select Complement of A, Union (A ∪ B), or Intersection (A ∩ B).
- Calculate: Click the Calculate button. The result shows the probability as a decimal and percentage, with a step-by-step explanation below.
Notes:
- For single events, favorable outcomes cannot exceed total outcomes.
- All probabilities are assumed independent for multiple events.
- Results are rounded to 4 decimal places.
Previous Results
| Result | Inputs | Date |
|---|
Frequently Asked Questions
Probability measures the likelihood of an event occurring, ranging from 0 (impossible) to 1 (certain).
Divide the number of favorable outcomes by the total number of possible outcomes.
The complement of event A is the probability that A does not occur, calculated as 1 - P(A).
