Probability Calculator
Run Probability calculations instantly — enter your data set to get summary statistics, probability values, and interpretation guidance.
Formula
P(A) = outcomes / total outcomes
Probability is the ratio of favorable outcomes to the total number of equally likely possible outcomes.
Worked Examples
Example 1: Coin Flip
Problem:Heads
Solution:1 success / 2 outcomes = 0.5
Result:50%
Example 2: Deck of Cards
Problem:Ace of Spades
Solution:1 card / 52 cards ≈ 0.019
Result:1.92%
Frequently Asked Questions
What is Probability?
Probability is the branch of mathematics concerning numerical descriptions of how likely an event is to occur, ranging from 0 (impossible) to 1 (certain).
How do I convert Probability to Odds?
If Probability is P, Odds = P : (1-P). For example, if P=0.25, Odds are 0.25 : 0.75, which simplifies to 1:3.
Can probability be greater than 1?
No. Probability represents a portion of the total possibilities, so it is always between 0 and 1 (inclusive).
How do I calculate probability of A AND B?
If independent: P(A and B) = P(A) × P(B). If dependent: P(A) × P(B|A).