Probability is the measure of how likely an event is to occur. It is expressed as a value between 0 and 1, where 0 means the event is impossible and 1 means the event is certain. For example, tossing a coin has two possible outcomes: heads or tails. The probability of getting heads is 1/2 = 0.5. In simple terms, probability helps us understand the chances of events in real life and is widely used in statistics, finance, science and risk management.

Our online tool is designed to be user-friendly and requires no advanced math knowledge. Just enter the total number of possible outcomes and the number of favorable events, then click on the calculate button. Within seconds, the tool displays the probability of the event happening as well as the probability of it not happening. For multiple events, you can input values for set A and set B to get detailed results including P(A), P(B), P(A∩B), P(A∪B) and conditional probability P(A|B).

Probability is calculated by dividing the number of favorable outcomes by the total number of possible outcomes. For example, if you roll a fair die, the probability of getting a “4” is 1/6 ≈ 0.167, since there is one favorable outcome and six total possible outcomes. The tool can also handle more advanced cases such as unions and intersections of events:

Union (A ∪ B): Probability of event A or event B occurring.

Intersection (A ∩ B): Probability of both events A and B happening simultaneously.

Conditional Probability (P(A|B)): The likelihood of event A occurring given that event B has already occurred.

Manual calculations can be tricky and prone to mistakes, especially when working with multiple events and conditional formulas. Our calculator eliminates these errors and gives you instant, reliable and accurate results. It is perfect for students learning probability, professionals dealing with statistics, or anyone who wants quick answers without going through tedious manual math. Since the tool is free, online and accessible on all devices, you can use it anytime and anywhere without restrictions.

✔ Easy-to-use interface that requires no prior knowledge of probability formulas.
✔ Accurate results for single and multiple event probability.
✔ Free and unlimited use without sign-ups or hidden charges.
✔ Cross-platform access — works on Windows, Mac, iOS android and Linux.
✔ Instant calculations without manual effort, making it ideal for education, business, or personal use.

Yes, your privacy is fully protected. The probability calculator doesn’t collect or require any personal information. You only need to enter numbers related to the problem you want solved and the tool instantly provides the probability. No login, registration, or sensitive data is ever requested, making it a secure option for everyone.