In this article we will discuss what is an 18 out of 25 and how to calculate it using our easy grade calculator. This calculator will allow you to quickly determine your percentage, letter grade and GPA for any test, quiz or exam. Simply input the total number of questions in the 'Questions' field and either the correct or incorrect answers, the rest will be calculated automatically. This is based on the fraction to percentage conversion formula which uses the number of correct answers divided by the total number of questions as the numerator.