What Grade Do I Need on My Final? Weighted Grade Math
Find what grade you need on your final from weighted scores and leftover course weight. Work a 70% example and see when a 90% target is already out of reach.
The score you need on a final is not a guess and it is not a simple average of the marks you already have. Leave unfinished work out of the table, then solve for the remaining share of the course. The grade calculator does that locally: current weighted grade, leftover weight, and the mark still required for a target overall.
In 2026, we ran the page defaults on September 12. Homework 88 at 20%, quizzes 92 at 15%, midterm 78 at 25%, and labs 95 at 10% produce a current grade of 86.29% on 70% of the course. A 90% overall target then needs 98.67% on the leftover 30%.
Weighted grades are not a simple average
NIST Dataplot defines a weighted mean as the sum of each value times its weight, divided by the sum of the weights. [1] OpenStax Principles of Finance 2e uses the same classroom-adjacent steps: multiply, add the products, divide by the total of the weights. [2]
On this page the formula is:
Current weighted grade = Σ(score × weight) ÷ Σ(entered weight)
The four default scores average 88.25% if you ignore weights. That figure is the wrong course grade. The midterm is 25% of the class; labs are 10%. Weighting pulls the current mark down to 86.29% because the weaker exam counts more.
Use the average calculator when every number should count equally. Use the grade page when the syllabus publishes category percentages.
Work the “what do I need on my final” formula
Leave the final out until it is scored. Remaining weight is 100 − entered weight. For a desired overall D:
Needed = (D × 100 − Σ(score × weight)) ÷ remaining weight
Default rows:
| Category | Score | Weight | Score × weight |
|---|---|---|---|
| Homework | 88 | 20 | 1,760 |
| Quizzes | 92 | 15 | 1,380 |
| Midterm | 78 | 25 | 1,950 |
| Labs | 95 | 10 | 950 |
| Entered | — | 70 | 6,040 |
Current = 6040 / 70 = 86.2857 displayed as 86.29
Needed for 90 = (9000 - 6040) / 30 = 98.67
A 100% remainder would finish near 90.40%. A 95% remainder would finish near 88.90%. A 92% course target on these inputs needs 105.33% on the leftover 30%, which the page flags as over 100.
If you only needed “what percent is 22 of 25?”, the percentage calculator is enough. The grade tool is for syllabus weights, not a single ratio.
The page does not stretch 70% of the course into 100%. Unfinished weight stays unfinished, which matches how most syllabi accumulate points.
Where the estimate stops
This is arithmetic, not a transcript. It does not drop a low quiz, apply a curve, round to a letter, or convert percentages into GPA. For credit-weighted GPA across several courses, use the GPA calculator.
If the syllabus is written in points, convert first: score = points earned ÷ points possible × 100, and weight = that category’s possible points ÷ the course total × 100. To add a column of raw points before converting, use the number sum calculator.
A needed score above 100 is a mathematical result. It is not a promise that extra credit exists. A needed score at or below 0 means the target is already met even if remaining work scores 0.
Does a 90% target always mean an A?
No. Letter cutoffs belong to the syllabus. Type the overall percentage you actually need.
Should I enter a guessed final to see my current grade?
No. A guessed final shrinks remaining weight and changes the “needed” figure. Leave unfinished work out.
Are scores uploaded?
No. Categories and numbers stay in the browser. Closing the tab clears the form. See the site privacy policy.
What to do next
Open the grade calculator, keep or edit the 70% sample, and confirm 86.29% and 98.67% before you trust a hand spreadsheet. If the leftover mark is over 100, lower the target or check whether the syllabus still has extra credit. Do not treat the page as an official gradebook.