Calculate Event Probability Instantly (Fraction, Decimal & %)
Calculate probabilities for events — shows fraction, decimal, percentage, complement, and odds. Supports single events and two independent events (AND/OR).
How to Use Probability Calculator
How to Use the Probability Calculator
Step 1: Choose a Mode
- Select "Single Event" to calculate basic probability for one event
- Select "Two Events — AND" to find the probability that both events occur
- Select "Two Events — OR" to find the probability that at least one event occurs
Step 2: Enter Outcomes
- Enter the number of favorable outcomes (e.g. 1 for rolling a specific number)
- Enter the total possible outcomes (e.g. 6 for a standard die)
- For two-event modes, repeat for Event B
Step 3: Calculate
- Click "Calculate" (or press Enter)
Step 4: Review Results
- View the probability as a simplified fraction, decimal, and percentage
- Check the complement (probability the event does NOT occur)
- See odds for and odds against
- For two-event modes, view P(A AND B), P(A OR B), and P(neither)
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