Calculadora de Probabilidade
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
P(A) = |favoráveis| / |totais|
About this calculator
The Probability Calculator is a practical tool to determine the chance of an event occurring. It uses the classic probability formula: number of favorable outcomes divided by total possible outcomes. For example, when rolling a six-sided die, the probability of getting a 4 is 1/6, as there is one favorable outcome out of six possible.
This calculator is useful in various everyday situations, such as predicting rain chances based on historical data, calculating the probability of winning in games of chance, or analyzing risks in business decisions. Simply enter the values for favorable and total events to get the result instantly.
Important precautions: ensure that the events are equally likely and mutually exclusive. For instance, when calculating the probability of drawing a heart from a deck of cards, remember there are 13 hearts out of 52 total cards. The calculator does not replace more complex analyses like conditional probability or distributions, but it is ideal for simple calculations.
Frequently asked questions
How do I calculate the probability of an event with this calculator?
Enter the number of favorable outcomes in the first field and the total number of possible outcomes in the second field. The result will be displayed as a fraction and decimal.
Does the calculator work for dependent events?
No, this calculator is only for independent and mutually exclusive events. For dependent events, use the conditional probability formula.
Can I use the calculator for multiple events?
Yes, but you must calculate each event separately. For simultaneous events, multiply the individual probabilities if they are independent.
What does a probability of 1 mean?
A probability of 1 means the event is certain to occur. For example, the probability of rolling a number between 1 and 6 on a die is 1.