How to calculate grades from points and percentages

Calculate a test percentage

For equally weighted questions, correct answers = total questions − wrong answers. With 20 questions and 3 wrong, you have 17 correct: 17 ÷ 20 × 100 = 85%. If questions carry different point values, use earned points instead of the number of questions.

Grade (%) = earned points ÷ possible points × 100

Combine assignments in a points-based course

Add the points before dividing. Suppose you earn 18 out of 20 on a quiz and 72 out of 80 on a test. Together that is 90 out of 100, or 90%. Averaging the two percentages is not generally correct when assignments have different possible points. For example, 10/10 and 50/100 combine to 60/110 = 54.55%, not the simple percentage average of 75%.

When to use weighted grades instead

If your syllabus says tests are 50%, quizzes 30%, and homework 20%, use category averages and those weights. Adding raw points across categories could give a different answer. Your course rules decide which method applies.

Convert a percentage to a letter grade

There is no universal letter-grade scale. Best Grade's test tool defaults to A at 93%, A− at 90%, B at 83%, and B− at 80%, with other cutoffs shown in the custom scale. At 85%, that example scale gives a B. Your teacher may use different boundaries or rounding rules.

Partial credit and ungraded work

Count half points or other partial credit in earned points. Leave genuinely ungraded work out of a current-grade calculation only if that matches your gradebook. A recorded zero is different from an assignment that has not yet been graded. Dropped scores, late penalties, and extra credit depend on your syllabus.