# Probability Calculator Calculate the probability of an event or outcome using our online calculator. By inputting relevant information such as the total number of possible outcomes and the number of favorable outcomes, you can determine the probability of the event occurring.

Single Event Probability Calculator

Results
Single Event Probability Value (decimal) Value (percent)
P(E) - -
P(E') - -

### Probability Formulas

The Single Event Probability Calculator uses the following formulas:

P(E) = n(E) / n(T) = (number of outcomes in the event) / (total number of possible outcomes)

P(E') = P(not E) = 1 - P(E)

Where:

P(E) is the probability that the event will occur,

P(E') is the probability that the event will not occur,

n(E) is the number of outcomes in the event E,

n(T) is the total number of possible outcomes.

Multiple Event Probability Calculator (A &B are independent events)

Results
Multiple Event Probability Value (decimal) Value (percent)
P(A) - -
P(A') - -
P(B) - -
P(B') - -
P(A ∩ B) - -
P(A ∪ B) - -
P(A | B) - -
P(B | A) - -

### Probability Formulas

The Multiple Event Probability Calculator uses the following formulas:

P(A) = n(A) / n(T)

P(A') = P(not A) = 1 - P(A)

P(B) = n(B) / n(T)

P(B') = P(not B) = 1 - P(B)

P(A ∩ B) = P(A) × P(B)

P(A ∪ B) = P(A) + P(B) - P(A ∩ B)

P(A | B) = P(A ∩ B) / P(B)

P(B | A) = P(A ∩ B) / P(A)

Where:

P(A) is the probability that event A occurs,

P(A') is the probability that event A does not occur,

P(B) is the probability that event B occurs,

P(B') is the probability that event B does not occur,

P(A ∩ B) is the probability that events A and B both occur,

P(A ∪ B) is the probability that events A or B occur,

P(A | B) is the probability that event A occurs, given that event B has occurred,

n(A) is the number of outcomes in the event A,

n(B) is the number of outcomes in the event B,

n(T) is the total number of possible outcomes.

Related

## what is Probability Calculator

A probability calculator is a tool that helps in calculating probabilities for various events or outcomes. It assists in determining the likelihood of an event occurring based on given information or known probabilities.

Here are a few common features of a probability calculator:

1. Simple Probability: This calculator can calculate the probability of a single event occurring. For example, if you want to determine the probability of rolling a specific number on a fair six-sided die, the calculator can provide the result.

2. Compound Probability: The calculator can calculate the probability of multiple events occurring together. For instance, if you want to find the probability of drawing two cards of a certain suit from a standard deck, the calculator can help you calculate it.

3. Conditional Probability: This calculator assists in calculating the probability of an event occurring given that another event has already occurred. For example, if you want to find the probability of selecting a red ball from a bag of colored balls after one blue ball has been removed, the calculator can perform the necessary calculations.

4. Probability Distributions: Some probability calculators provide functions to calculate probabilities for specific probability distributions. You can input different parameters and variables to determine probabilities associated with specific distributions like the normal distribution, binomial distribution, Poisson distribution, etc.

5. Random Variables: Advanced probability calculators may allow you to work with random variables. You can specify the distribution and parameters of a random variable and then calculate probabilities associated with that variable.

6. Cumulative Probability: The calculator can calculate cumulative probabilities, such as finding the probability of observing a value less than or equal to a given value in a distribution.

7. Combinations and Permutations: The calculator can assist in calculating combinations and permutations, which are often used in probability calculations involving combinations of events or arrangements.

Many online probability calculators are available that offer these features and more. Additionally, there are programming languages and statistical software packages like R, Python, or Matlab that have built-in functions for probability calculations and offer more advanced capabilities.

When using a probability calculator, it is essential to input the correct information and understand the assumptions and limitations of the calculations being performed.

## Probability Calculator example

Certainly! Let's consider an example of calculating the probability of rolling a specific number on a fair six-sided die.

Step 1: Define the event of interest.

In this case, we want to calculate the probability of rolling a specific number on the die. Let's say we are interested in rolling a 3.

Step 2: Determine the total number of possible outcomes.

A fair six-sided die has six possible outcomes, which are the numbers 1, 2, 3, 4, 5, and 6.

Step 3: Determine the number of favorable outcomes.

Since we want to roll a 3, there is only one favorable outcome (rolling a 3).

Step 4: Calculate the probability.

The probability is calculated by dividing the number of favorable outcomes by the total number of possible outcomes:

Probability = Number of Favorable Outcomes / Total Number of Possible Outcomes

For rolling a 3 on a fair six-sided die:

Probability = 1 / 6 ≈ 0.1667 or 16.67%

Therefore, the probability of rolling a 3 on a fair six-sided die is approximately 0.1667 or 16.67%.

Please note that this is a simple example of calculating a probability for a specific event on a fair die. The principles and calculations can be applied to various other probability scenarios, such as calculating the probability of multiple events or using more complex probability distributions.