- Enter the number of events that occurred n(E).
- Enter the number of possible outcomes n(T).
- Click the “calculate” button.
- Use the reset button to enter new values.

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Probability calculator evaluates the probability of occurring events out of total number of possible outcomes. This event probability calculator finds single-event probability. For example; a coin is tossed 90 times and we have to calculate the chances of occurring head in the 1^{st} five times.

Probability is simply how likely something is to happen. It is the outcome of a random event i.e. if we toss a coin we cannot say what will be the result whether it will be head or tail until the event happens. The probability ranges between 0 and 1.

If the probability of an event is 0.6 then it means there is a 60% chance of happening that event. The probability theory contains some sub-terms in it, to understand the concept of probability first we have to go through these basic terms.

**Experiment:**To find well-defined outcomes we do experiments.**Trial:**The term “trial” represents how many times an experiment is performed.**Outcome:**It is the possible result.**Sample space:**All the possible results together make a sample space. It is represented by curly brackets {}.**Event:**The sample space is a set, and all of its subsets are known as events.

The general formula to calculate the single event probability is as follows:

*Probability = number of events occurred n(E) / number of possible outcomes n(T) *

We can calculate the probability of a sample space by following the below steps.

- Check the number of all possible outcomes n(T)
- Find out the number of events that occurred n(E)
- Divide n(E) by n(T)

To understand the method more precisely, have a look at the following examples.

**Example 1: **

A fair die is rolled one time, what are the chances of coming the face 6?

**Solution: **

**Step 1:** Check the number of all possible outcomes n(T)

A die has six faces so n(T) = 6

**Step 2:** Find out the number of events that occurred n(E)

The die is rolled one time so n(E) = 1

**Step 3:** Calculation

Probability = n(E) / n(T)

Probability = 1/6

Probability = 0.1667

Probability = **16.67%**

*Probability and statistics*| Encyclopedia Britannica.*Probability: The basics (article)*| Khan Academy.