How do I calculate my grade if the weights don't add up to 100?

Divide by whatever the weights do sum to. Homework 88 at 15, labs 91 at 25, and a midterm 76 at 25 sum to 65 weight points, so the grade so far is 5,495 ÷ 65 = 84.54 — a true average over everything graded to date.

How much is one point on the final worth to my course grade?

The final's weight divided by 100. With a final worth 35% of the grade, each point scored on it moves the course grade by 0.35 points — which is why a ten-point swing on the final moved the worked example by exactly 3.5 course points.

How do I weight a points-based course?

Each item's weight is its points divided by the course total: a 200-point final in an 800-point course is 25%. Enter the percent earned on the item — 168 of 200 points is 84% — next to that weight, and the weighted average handles the rest.

Is 83.65 a B or a B−?

Under the x7/x3 convention this site uses, B runs 83–86.99, so 83.65 is a flat B and B− would start below 83. Letter boundaries vary by instructor, though — the percent is exact, and the syllabus decides the letter.

Guides

How do you calculate a weighted course grade?

By GradeLab · Published June 10, 2026 · Updated June 10, 2026

Multiply each category score by its weight, add the products, and divide by the sum of the weights — homework 88 at 15%, labs 91 at 25%, a midterm 76 at 25%, and a final 82 at 35% works out to (88 × 15 + 91 × 25 + 76 × 25 + 82 × 35) ÷ 100 = 83.65, a B.

The weighted-average formula, computed by hand once

A weighted course grade is a weighted average: grade = Σ(score × weight) ÷ Σ(weight). Take a syllabus that weights homework 15%, labs 25%, the midterm 25%, and the final 35%, with scores of 88, 91, 76, and 82. The products are 88 × 15 = 1,320, 91 × 25 = 2,275, 76 × 25 = 1,900, and 82 × 35 = 2,870. They sum to 8,365, and dividing by the 100 points of total weight gives a course grade of 83.65.

Doing the multiplication once by hand shows what weighting actually does: it redistributes influence. The 91 in labs and the 76 on the midterm carry identical 25% weights, so they pull on the grade equally — but the 88 homework average, the best habit-driven score in the course, moves the total less than any other category because it carries only 15%. Weighted grading is the syllabus's statement about what the instructor considers most important, written in arithmetic.

Reading your grade mid-semester, before the final exists

Most of the semester, at least one category has nothing in it. Before the final is taken, the same student holds homework 88 at 15, labs 91 at 25, and the midterm 76 at 25 — weights summing to 65, not 100. The calculator averages over the weight that exists: (1,320 + 2,275 + 1,900) ÷ 65 = 84.54. That is the honest mid-semester reading — the grade earned on everything graded so far.

Notice the standing fell from 84.54 to 83.65 once the 82 final arrived: scoring below your running average in a heavy category drags the average down, and the 35% weight made the final the strongest single pull in the course. The mid-semester number is a baseline, not a prediction — it tells you where you stand and leaves the final's weight as the open question.

What-if planning with the same arithmetic

Because the formula is linear, what-if questions are cheap to answer. Replay the example with a 92 on the final instead of an 82 and the course grade becomes (1,320 + 2,275 + 1,900 + 92 × 35) ÷ 100 = 87.15 — ten more points on the final bought 3.5 course points, exactly the final's 35% weight applied to the difference. Each point earned in any category moves the course grade by that category's weight divided by 100.

That per-point rate is the study-time exchange rate. With this syllabus, a point on the final is worth 0.35 course points while a point on homework is worth 0.15 — so an hour that can raise the final by a point beats an hour that raises homework by two. To plan a target precisely, run the weighted grade on everything already earned, then use the needed-score view to solve for the final-exam score the target requires instead of guessing.

Converting a points-based syllabus into weights

Plenty of courses skip percentage categories and grade out of a points pool — say 800 points across the semester. The weighted machinery still applies because every item's weight is just its share of the pool: a 200-point final in an 800-point course is 200 ÷ 800 = 25% of the grade, and a 40-point quiz is 5%. Convert each item or category to its percentage share and the weighted-grade view models the course exactly.

The score that goes next to each weight is the percent earned on that item, not the raw points. Earn 168 of the final's 200 points and the entry is 168 ÷ 200 = 84% against the 25% weight — which on its own reads as a B under the common letter scale. Keeping points and percents straight is the main bookkeeping hazard in the conversion; the arithmetic afterward is identical.

The letter at the end is a convention, not a rule

An 83.65 reads as a B under the widespread U.S. scale this site discloses — the one that splits each letter band at the x3 and x7 boundaries, so B runs from 83 to 86.99 and the 87.15 from the what-if scenario crosses into B+ territory. Both readings are conventions, not standards: institutions and individual instructors set their own cutoffs, some award no plus or minus grades at all, and others round up at boundaries by stated policy or quiet habit.

The percent the formula produces is exact for the scores and weights you enter; everything after it belongs to your syllabus. Weights change between course sections, drop-lowest rules remove a score before the average is taken, and extra credit lands differently in every course. Use the calculator to know your number and what each remaining assignment is worth — and treat the letter, the rounding, and any boundary case as questions for the syllabus or the instructor, not the arithmetic.

Questions

How do I calculate my grade if the weights don't add up to 100?: Divide by whatever the weights do sum to. Homework 88 at 15, labs 91 at 25, and a midterm 76 at 25 sum to 65 weight points, so the grade so far is 5,495 ÷ 65 = 84.54 — a true average over everything graded to date.
How much is one point on the final worth to my course grade?: The final's weight divided by 100. With a final worth 35% of the grade, each point scored on it moves the course grade by 0.35 points — which is why a ten-point swing on the final moved the worked example by exactly 3.5 course points.
How do I weight a points-based course?: Each item's weight is its points divided by the course total: a 200-point final in an 800-point course is 25%. Enter the percent earned on the item — 168 of 200 points is 84% — next to that weight, and the weighted average handles the rest.
Is 83.65 a B or a B−?: Under the x7/x3 convention this site uses, B runs 83–86.99, so 83.65 is a flat B and B− would start below 83. Letter boundaries vary by instructor, though — the percent is exact, and the syllabus decides the letter.