Grading

Turn 85/100 Into a Letter: Grading Math

A raw 85 out of 100 is an 85% — but the percent the syllabus actually uses is a weighted average across assignments, quizzes and exams. Convert a score the easy way in the "what percent" mode, then weigh each part correctly so the letter at the end is the one you intended.

First, the plain score-to-percent

Percent = score ÷ max × 100. An 85/100 is 85%; a midterm of 23/30 is 76.7%. That single conversion is the "X is what % of Y" mode doing one job.

Then the weighted average — and the trap

Few courses average raw points. Say the weights are 30% homework, 70% exam:

• Homework 95%, exam 75% → (95×0.30) + (75×0.70) = 28.5 + 52.5 = 81%.

The classic mistake is averaging the percents directly: (95 + 75) ÷ 2 = 85%, which overstates the grade by 4 points. Because the exam carried more weight, the 75 hit harder. Weighted math is percent × weight, summed — not a plain average.

Work the weights as percent of the course

Weights must add to 100% of the grade. If the syllabus lists 20% quizzes, 30% projects, 50% final, your final percent is quiz%×0.20 + project%×0.30 + final%×0.50. Any weight overhang or shortfall quietly re-weights your score. The calculator keeps each contribution straight.

What letter does 81% earn?

Depends on the scale, but under a typical 90/80/70/60 cut: 81% is a solid B. Knowing your percentile position — as a percent of every student — matters more to ranking, and that is another percent question the tool answers instantly.