★ SCHOOL · GRADES · CALCULATOR
Homework is worth 20% and you have 88. Quizzes are worth 20% and you have 76. Tests are worth 40% and you have 84. That is 66.4 points of the 80 so far — 83.0% — and the final is worth the last 20%. You need 68.0% on the final for a B — and an A needs 118.0%, which is impossible. Enter your own weights and scores below.
Enter each category’s weight and your score in it. The calculator adds up the points you have already earned, works out your grade on the work done so far, and solves for the final-exam score you need for your target grade — for an A, a B, and a C. Leave the final-exam score blank if you have not taken it yet; put in a guess (the default is 85) to see your overall grade.
A weighted grade does not average your scores — it averages them by importance. Each category contributes its weight times its score, divided by 100. Homework at 20% with a score of 88 contributes 20 × 88 ÷ 100 = 17.6 points. Quizzes at 20% with 76 contribute 15.2 points. Tests at 40% with 84 contribute 33.6 points. Add them: 66.4 points out of the 80 points counted so far — which is 83.0% on the work done. The final, worth 20%, can add at most 20 more points. That is why a single number — your plain average of 88, 76, and 84 is 82.7% — is close to but not the same as your weighted 83.0%: the tests, where you scored 84, count double the homework and quizzes.
Setup: Homework 20% at 88, quizzes 20% at 76, tests 40% at 84, final 20% not yet taken, target 80% (a B).
Line 1 — points earned. 20 × 88 ÷ 100 = 17.6; 20 × 76 ÷ 100 = 15.2; 40 × 84 ÷ 100 = 33.6. Total: 66.4 points of 80 so far.
Line 2 — grade so far. 66.4 ÷ 80 × 100 = 83.0%. On the work done, you are at a B.
Line 3 — what the final must do. You need 80 points total for a B (80% of 100). You have 66.4, so the final must add 13.6 points: 13.6 ÷ 20 × 100 = 68.0% on the final. That is the solver’s core equation: needed = (target − earned) ÷ final weight × 100.
Line 4 — the A that is not there. For an A you need 90 points, so the final must add 23.6: 23.6 ÷ 20 × 100 = 118.0%. No score that high exists — even a perfect 100 on the final only gets you to 86.4%. The A is gone, and the calculator says so plainly instead of pretending otherwise.
Line 5 — the C floor. For a C you need 70 points, so the final must add 3.6: 3.6 ÷ 20 × 100 = 18.0%. Almost any score on the final keeps you above a C.
Line 6 — the what-if. Score 85% on the final and it adds 20 × 85 ÷ 100 = 17 points: 66.4 + 17 = 83.4% overall — a solid B, barely above where you started, because the final is only a fifth of the grade.
Branch — all categories complete (no final): weights 25/25/50/0 with the same scores give 25 × 88 ÷ 100 = 22, plus 19, plus 42 = 83.0% — the plain weighted average, with no final left to take.
Branch — zero-weight category: set quizzes to 0% and tests to 60% (weights 20/0/60/20) and you have 17.6 + 50.4 = 68.0 of 80 points (85.0%). The B now needs only 60.0% on the final, and 85% on the final gives 85.0% overall.
Branch — extra credit: score 105% on tests (extra credit allowed up to 120) and you have 17.6 + 15.2 + 42 = 74.8 of 80 points (93.5%). The B needs only 26.0% on the final, and 85% on the final gives 91.8% overall — an A.
Branch — the error case: leave the homework score blank while homework is worth 20% and the calculator refuses — every weighted category needs a score. Set the weights to 20/20/40/10 and it refuses too: they add to 90%, not 100%, and the error tells you to scale each weight by 1.11 to normalize them.
| Letter | Percent range | What it means here |
|---|---|---|
| A | 90–100 | Needs 118.0% on the final at the defaults — impossible |
| B | 80–89 | Needs 68.0% on the final at the defaults |
| C | 70–79 | Needs 18.0% on the final at the defaults |
| D | 60–69 | Already secured — even 0% on the final leaves 66.4% |
| F | Below 60 | Not possible at the defaults — you already have 66.4 points |
Letter scales vary by school: some schools set A at 93, some use plus and minus grades (A− at 90, B+ at 87), and some curve. Check your syllabus — the calculator uses the common 90/80/70/60 scale above, and the target-grade field lets you aim at any percent, whatever your school calls it.
| Output | Formula | What it means |
|---|---|---|
| Points earned so far | Σ (weight × score ÷ 100) | 66.4 of 80 points at the defaults — the points already in the bank. |
| Grade on work so far | earned ÷ completed weight × 100 | 83.0% at the defaults — your grade on the work done, ignoring the final. |
| Need on the final (target) | (target − earned) ÷ final weight × 100 | 68.0% for a B (80%) at the defaults. |
| Need on the final (A) | (90 − earned) ÷ final weight × 100 | 118.0% — impossible, even a perfect score is not enough. |
| Need on the final (C) | (70 − earned) ÷ final weight × 100 | 18.0% — almost any score on the final keeps you above a C. |
| Overall if the final is 85% | earned + final weight × 85 ÷ 100 | 83.4% at the defaults — a solid B. |
| No final (weight 0) | earned ÷ completed weight × 100 | 83.0% — the plain weighted average, no final left to take. |
| Weights not 100% | sum check | Error — scale each weight by 100 ÷ sum to normalize them. |
The math is exact for the weights and scores you enter, but the model is only as good as the syllabus it copies. Letter scales vary by school — some set A at 93, some use plus/minus grades, some round 89.5 up to an A and some do not. Some teachers drop the lowest quiz or homework score, which this calculator does not model: remove the dropped score from your average before entering it. Some classes weight categories differently for different students (extra-credit assignments, curved tests), and a curved score should be entered after the curve is applied. Scores over 100 are allowed up to 120 for extra credit; beyond that the calculator refuses. Weights must add to 100 — if your syllabus lists weights that add to something else, scale each one by 100 divided by the sum, exactly as the error message says. This is a planning tool, not an official grade — your teacher’s gradebook is the final word.
Bright Side Kit. "Weighted Grade Calculator: What You Need on the Final." https://brightoolbox.com/weighted-grade-calculator/ Accessed October 24, 2026.Multiply each category’s weight by its score, divide by 100, and add the results. Homework 20% at 88 gives 17.6 points, quizzes 20% at 76 gives 15.2, tests 40% at 84 gives 33.6 — 66.4 points in total. Divide by the weight counted so far (80) and you get 83.0%. The final, worth 20%, can add up to 20 more points.
The calculator shows an error and tells you how to fix it: scale each weight by 100 divided by the sum. Weights of 20/20/40/10 add to 90%, so multiply each by 1.11 (100 ÷ 90) to get 22.2/22.2/44.4/11.1, which add to 100. Or check your syllabus — you may have missed a category, such as participation.
Not at the defaults. You would need 118.0% on the final for a 90% overall, and no score that high exists — even a perfect 100 on the final only gets you to 86.4%. The calculator says so plainly. The realistic target is a B, which needs 68.0% on the final. Check the number before finals week, not after.
Leave the final-exam score blank — the solver still works and tells you what you need on it for an A, a B, and a C. Put in a guess (the default is 85) to see your overall grade if you score that much. Either way, the points you have already earned — 66.4 of 80 — do not change.
Yes, up to 120 — extra credit counts. Score 105% on tests and you have 74.8 of 80 points (93.5%), so the B needs only 26.0% on the final and 85% on the final gives 91.8% overall. Above 120 the calculator refuses, because no real class gives that much extra credit.
Drop it yourself before entering the numbers: recompute that category’s average without the dropped score, then enter the new average. This calculator does not model dropped scores — it takes the category averages you give it. The same applies to curved tests: enter the score after the curve is applied.
Points are the weighted contributions: 66.4 points out of 100 possible, with 80 of those points decided so far. Percent is the same number scaled to the work done: 66.4 ÷ 80 = 83.0%. The points tell you how much is left to win (20 points on the final); the percent tells you where you stand right now.
Set its weight to 0 and the calculator ignores it — its score does not matter. Set the final’s weight to 0 and there is no final to take: the result is the plain weighted average over the completed categories, 83.0% at the defaults (weights 25/25/50/0). A zero-weight category with a blank score is fine; a weighted category with a blank score is an error.