Probability Calculator
Calculate probabilities, permutations, and combinations.
Basic probability
Example: 3 favorable outcomes out of 10 possible
Probability
30.0%
70.0%
P(A)
0.3000
30.00%
Odds for
3:7
Odds against
7:3
Complement
P(A') = 1 - P(A)0.7000
Formula
P(A) = 3 / 10 = 0.3000
What is probability?
Probability measures the chance that an event will occur, expressed as a number between 0 (impossible) and 1 (certain), or as a percentage. It's calculated by dividing favorable outcomes by total outcomes.
Permutations vs Combinations
In permutations order matters (ABC ≠ BAC). In combinations it doesn't (ABC = BAC). That's why there are always more permutations than combinations for the same values.
Real-world applications
Used in statistics, insurance, games of chance, genetics, quality control, weather prediction, and decision-making under uncertainty.