Probability Calculator
Need to calculate probability quickly? Our free Probability Calculator helps you solve chance problems using accurate formulas for combinations, permutations, independent/dependent events, and conditional probability. Whether you're a student tackling statistics homework, a researcher analyzing data, or a gambler assessing odds, this tool makes complex calculations effortless.
Result
| No of possible event that occured | ||
|---|---|---|
| No of possible event that do not occured |
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Your Ultimate Probability Solver
Probability Calculation Formulas with Examples:
1. Basic Probability (Single Event)
Formula:
P(A)=Number of favorable outcomesTotal possible outcomesP(A)=Total possible outcomesNumber of favorable outcomes
Example:
Problem: What’s the probability of rolling a 3 on a 6-sided die?
Favorable outcomes: 1 (rolling a 3)
Total outcomes: 6 (1, 2, 3, 4, 5, 6)
Calculation: P(A)=16≈16.67%P(A)=61≈16.67%
2. Multiple Independent Events (AND Rule)
Formula:
P(A∩B)=P(A)×P(B)P(A∩B)=P(A)×P(B)
Example:
Problem: What’s the probability of flipping heads and rolling a 4?
P(Heads): 1221
P(Rolling 4): 1661
Calculation: 12×16=112≈8.33%21×61=121≈8.33%
3. Mutually Exclusive Events (OR Rule)
Formula:
P(A∪B)=P(A)+P(B)P(A∪B)=P(A)+P(B)
Example:
Problem: What’s the probability of drawing a heart or a king from a deck?
P(Heart): 1352=145213=41
P(King): 452=113524=131
P(King of Hearts): 152521 (subtract overlap)
Calculation: 14+113−152=1652≈30.77%41+131−521=5216≈30.77%