Grade calculator: your grade, and what you need on the final

Weighted grades, worked through

When a syllabus says homework is 20%, quizzes 15%, the midterm 25% and the final 40%, each part counts that much of the grade. Before the final, the grade so far is the weighted average of the parts you have: multiply each score by its weight and divide by the weights graded so far.

With the example's 92 in homework, 85 in quizzes and 78 on the midterm: (92 × 20 + 85 × 15 + 78 × 25) ÷ 60 = 5,065 ÷ 60 = 84.42%, a B. Dividing by 100 instead of 60, as if the final were a zero, would give 50.65%, which is why grade portals can look alarming early in a term.

Scores can be typed as points: 45/50 counts as 90%, and so does “45 of 50”. If the weights do not add up to 100, the bar above the table says so in orange; the grade is still worked out from the parts that have scores, so a syllabus with extra credit or a part left off still gives a sensible answer.

The score you need on the final

If the final is worth w percent and your grade so far is g, finishing with a target t needs a final score of (t − g × (1 − w)) ÷ w. With 84.42% so far and a final worth 40%:

The calculator rounds the needed score up, so reaching it really is enough. When the answer is above 100%, it says the grade is out of reach without extra credit; when it is 0 or less, you already have that grade whatever happens on the final. A target of 93%, an A on the usual scale, would need 105.88% here.

Letter grades and their cut-offs

The Letter uses a common US scale: A from 93, A− from 90, B+ 87, B 83, B− 80, C+ 77, C 73, C− 70, D+ 67, D 63, D− 60, and F below 60. Many schools and teachers use a 90/80/70/60 scale without pluses and minuses, and some round 89.5 up to an A, so treat the letter as a guide and the percentage as the fact.

To turn a semester of letter grades into a grade point average, use the GPA calculator. For a single test, the percentage calculator turns 38 out of 45 into 84.44%.