Statistics
Probability Calculator
Enter favorable and total outcomes to translate chances into probability, percent, and odds formats.
probabilityoddslikelihood
Probability
Quickly translate event counts into probability, percentage, and odds.
Probability
0.25
Percent
25%
Odds (favorable : unfavorable)
3 : 9
Complement probability
0.75
Probability basics
P(event) = favorable outcomes / total outcomes
The tool also reports odds as favorable to unfavorable counts so you can communicate results in any format.
How to use
- Enter the number of favorable outcomes.
- Enter the total possible outcomes in the sample space.
- See probability as a decimal, percentage, and odds in one glance.
Example
Input: Favorable = 3, Total = 12
Output: Probability = 0.25, Percent = 25%, Odds = 1:3
FAQ & notes
What if favorable exceeds total?
The calculator flags the result as invalid because favorable outcomes cannot exceed the total outcomes.
Can I express probability as 1 in N?
Yes—the odds output presents the ratio so you can restate it as 1 in N or keep the colon notation.