Probability calculator
Enter favourable and total outcomes to get the probability.
Probability calculator
Calculate the probability of a single event from the number of favourable outcomes and the total number of equally likely outcomes. The result is shown as a percentage and a decimal.
Formula
P = favourable ÷ total. Example: rolling a specific number on a die is 1 ÷ 6 ≈ 16.67%. Probability is always between 0 (impossible) and 1 (certain), i.e. 0%–100%.
Frequently asked questions
How do I calculate probability? Divide the favourable outcomes by the total possible outcomes.
Can probability be over 100%? No — for a single event it ranges from 0% to 100%.