Math
Probability Calculator
Calculate probability, combinations, permutations, and odds
FAQs
What is the difference between combinations and permutations?
Combinations count selections where order does not matter, while permutations count arrangements where order matters.
How to Use the Probability Calculator
Calculate the probability of single and combined events.
- Enter the number of favorable outcomes.
- Enter the total number of possible outcomes.
- See the probability as a fraction, decimal, and percentage.
Probability Formulas
Single Event
P(A) = favorable / total
Outcomes you want divided by all equally likely outcomes.
Example:
Input: rolling a 6
Calculation: 1 / 6
Result: ≈ 16.7%
Independent Events (AND)
P(A and B) = P(A) × P(B)
Multiply probabilities of independent events.
Example:
Input: two heads
Calculation: 0.5 × 0.5
Result: 25%
Real-World Use Cases
Games & Odds
Compute dice, card, and lottery odds.
Risk Estimation
Combine event probabilities.
Tips
Tips
- Probabilities range from 0 (impossible) to 1 (certain).
- Add for OR (mutually exclusive), multiply for AND (independent).
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