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Probability Calculator



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Event A
Event B

What is Probability?

Probability measures the likelihood of an event to happen and when the event will happen. It also checks the position of a number. Probability with number 0 is described as impossibility of an event and 1 is described as certainty.

The probability also helps us understanding how to find expected value by using expected number calculator and the calculations of variance.

Probability Formula

The probability formula is defined as the number of favorable outcomes divided by the total number of outcomes.

$$\text{P(A)}=\frac{\text{Number of favorable Outcome}}{\text{Total Number of Favorable Outcomes}}$$

P(A) represents the probability of an event, n(E) represents number of favorable outcomes and n(S) represents total number of events. Probability formula is also written as


The probability formula makes us easy to calculate summation and learn deep about the calculations of midpoint.

Types of Probability

The probability has 3 major types which includes

  1. Classical
  2. Relative Frequency Definition
  3. Subjective Probability

With statistics and probability, you can also find trigonometry calculators on our portal like slope equation calculator and cylinder volume formula calculator.

Probability Rules

There are 2 major probability rules which include

  1. Addition Rule
  2. Multiplication Rule

You can also use matrix multiplication calculator in order to learn multiplication rules.

Addition Rule in Probability

If there is job 1 in P ways and job 2 in q ways and both are related, we can do only 1 job at given time in p+q ways.

Multiplication Rule in Probability

If there is job 1 in P ways and job 2 in q ways and both are not related, we do both jobs at given time in p*q ways.

Learn how the concepts of midpoint and arithmetic sequence differs from each other. Use midpoint calculator and arithmetic sequence calculator to solve queries on runtime.

Can the Probability be negative?

The probability value of an outcome can never be negative. The probability value always remains postitive. For unobservable events or conditional probabilities, quasiprobability can allow a negative probability for distribution only.

How to find Probability?

Probability is expressed between 0 and 1. 1 is examined as accurate (True) and 0 is taken as incorrect (False). Higher Probability of event assures that this event will occur.

Probability helps us to predict the outcome of an area or value, to learn more about specific areas and math calculations, try rectangular area calculator and shaded region of a circle calculator.

Main functions of Probability

Main functions of Probability

There are different probability functions which we need to know while calculating the probability. These functions are

  • Probability of A occurring given times
  • Probability of A NOT occurring
  • Probability of A occurring
  • Probability of B occurring given times
  • Probability of B NOT occurring
  • Probability of B occurring
  • Probability of A occurring given times and B occurring given times
  • Probability of neither A nor B occurring
  • Probability of both A and B
  • Probability of A occurring given times but not B
  • Probability of B occurring given times but not A
  • Probability of A occurring but not B
  • Probability of B occurring but not A

If set of possibilities are large and only few results are successful, then the probability of the outcome is tiny like P(B)=0.00001. It's always suitable to use the scientific notation in a sequence not to mix up the number of zeros.

What is Probability Calculator?

Probability Calculator is a risk analysis tool which is available online. It is designed for finding the probability for single and multiple events.

Probability Calculator helps to examine the relationships of likelihood within two different events and completes the calculations without any error. If you are looking for how to calculate probability? our probability distribution calculator is the best option for you.

Benefits of using Probability Calculator

Probability Calculator allows to calculate probability of single and multiple events easily. For example, if event A and B has the chances of 50% each, what are possible chances of happenings?

This Calculator provides 6 research goals, plus 7 more when you enter its advance level. This calculator saves a lot of time as long as one knows how to find the probability of separate events.

Besides using probability calculator, you can also use our other math related calculators like factor table calculator and gcf algebra calculator.

Problems handled by Probability Calculator

  • Find P(A), given P(A')
  • Find P(A'), given P(A)
  • Find P(A), given P(B), P(A ∩ B), and P(A ∪ B)
  • Find P(A), given P( B|A ) and P(A ∩ B)
  • Find P(A'), given P(B), P( B|A ) and P(A ∪ B)
  • Find P(A'), given P(B), P(A ∩ B), and P(A ∪ B)
  • Find P( B|A ), given P(A) or P(A'), P(B), and P(A ∪ B)
  • Find P( B|A ), given P(A) or P(A'), and P(A ∩ B)
  • Find P(A ∪ B), given P(A) or P(A'), P(B), and P(A ∩ B)
  • Find P(A ∩ B), given P(A) or P(A'), P(B), and P(A ∪ B)

Probability calculator solves problems which are directed by three primary rules of probability including (addition rule, subtraction rule and multiplication rule).

How to use Probability Calculator?

Probability calculator is free and easy to use. You just need to follow below steps

  • Step #1: Define the probabilities of single or multiple events you want to calculate. Probabilities must have two separate events.

    Probability of A: P(A)


    Probability of B: P(B)

  • Step #2: Find the Probability of an event. When you know how to examine the likelihood relationships of separate events, select your research goals and get the required results.

    To perform the task, select an option from 6 different research goals:

    • Option 1: P(A') – Probability of A not occurring
    • Option 2: P(B') – Probability of B not occurring
    • Option 3: P(A ∩ B) – Probability of A and B both occurring
    • Option 4: P(A ∪ B) – Probability that A or B or Both occurs
    • Option 5: P(A △ B) – Probability that A or B occurs but NOT both
    • Option 6: P((A ∪ B)') – Probability of neither A nor B occurring
  • Step #3: Click on the calculate button. The intersection calculator applies the analytical technique to reach the research goal and generate summary report to explain the analysis and research findings.

We hope our probability distribution calculator worked fine for you. You can also get benefit using our step by step integral calculator and differential calculator in order to learn integration and differentiation.

Alan Walker

Last updated: September 09, 2020

Studies mathematics sciences, and Technology. Tech geek and a content writer. Wikipedia addict who wants to know everything. Loves traveling, nature, reading. Math and Technology have done their part, and now it's the time for us to get benefits.

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Victorina Moreno González
I think your explanation is very good, thank you very much, understood.