Probability Calculator

Estimating how likely something is becomes straightforward here, whether the question is broad or personal. Picture weighing the 2026 global economic forecast, where the IMF puts the odds of moderate growth at 70%, or sizing up your startup's shot at funding among the 50,000 venture capital firms projected to be active in 2026—the same underlying logic applies. Anyone who reasons from data, from business strategists to students, can put it to work.

The engine rests on a few core formulas. For a single event, probability P equals the number of favorable outcomes divided by the total number of possible outcomes. When two events A and B are independent, their joint probability is P(A and B) = P(A) * P(B). When A and B are mutually exclusive, the chance that either occurs is P(A or B) = P(A) + P(B).

Single-event accuracy hinges on counting outcomes honestly—every favorable case and every possible case must be accounted for. With combined events, the key distinction is whether they are independent, meaning one has no bearing on the other, or mutually exclusive, meaning they cannot both happen at once. Reaching for the independent-events formula when the events are actually mutually exclusive is a classic error that quietly corrupts the answer.