Probability Calculator
Calculate probability, complement, and odds from favorable outcomes and total outcomes.
The Probability Calculator computes the likelihood of an event occurring based on the number of favorable outcomes and total possible outcomes.
Enter the number of favorable outcomes and the total number of possible outcomes. The calculator gives you the probability (0 to 1), percentage, complement (probability of NOT occurring), and the odds both for and against the event.
Probability is the foundation of statistics, risk assessment, gambling, insurance, and decision-making. Understanding odds vs probability is important: odds of 3:7 means probability of 3/10 = 30%.
Frequently Asked Questions
What is the difference between probability and odds?
Probability is favorable/total (e.g., 3/10). Odds are favorable/unfavorable (e.g., 3:7 or 3/7). They represent the same likelihood differently.
What is the complement of a probability?
The complement is 1 minus the probability. If P(rain) = 0.3, then P(no rain) = 0.7.
Can probability be greater than 1?
No. Probability ranges from 0 (impossible) to 1 (certain). If your result exceeds 1, check that favorable outcomes do not exceed total outcomes.