About Probability Calculator
The Probability Calculator helps you work out the probability of an event and explore basic counting results. Enter the number of favorable outcomes and total outcomes to calculate probability and odds. You can also enter n and r to calculate combinations and permutations.
How to Use
- Enter the number of possible successful outcomes in Favorable outcomes.
- Enter the total number of possible outcomes in Total outcomes.
- Enter n and r to calculate combinations and permutations. Here, n is the total number of items, and r is the number selected.
- Click Calculate.
- Review the probability, odds, combination, and permutation results. Use Copy or Download if you want to keep them.
The result depends on the values you enter and assumes the outcomes are defined appropriately for the calculation. Probability estimates do not guarantee what will happen in a real-world situation.
FAQ
How do I calculate probability with this tool?
Enter the number of favorable outcomes and the total number of outcomes, then click Calculate. The calculator displays the probability and odds.
What do “favorable outcomes” and “total outcomes” mean?
Favorable outcomes are the outcomes that match the event you are measuring. Total outcomes are all possible outcomes in the scenario.
What do n and r mean?
For combinations and permutations, n is the total number of items, and r is the number of items selected from that total.
What is the difference between a combination and a permutation?
A combination counts selections where order does not matter. A permutation counts arrangements where order matters.
Does a calculated probability guarantee an outcome?
No. Probability describes how likely an outcome is based on the numbers entered. It cannot guarantee what will happen in a particular event.