The calculation
How to calculate your semester grade
Quick answer: multiply each part of the semester by its weight as a decimal, then add the results. Two quarters at 40% each and a final at 20% means quarter grades do most of the work before you ever sit the exam.
Write each weight as a decimal. A quarter worth 40% uses a weight of 0.40.
A worked example
Say you got an 88 in the first quarter, a 79 in the second, and an 85 on the final exam, on the classic 40/40/20 weighting:
- 01
Convert each weight to a decimal: 40% becomes 0.40, 20% becomes 0.20
- 02
Multiply each grade by its weight: 88 × 0.40 = 35.2, then 79 × 0.40 = 31.6, then 85 × 0.20 = 17
- 03
Add the results: 35.2 + 31.6 + 17 = 83.8
- 04
Read it against the letter scale: 83.8 is a B
The second quarter's 79 cost real ground, but because the final only carries 20%, the 85 on the exam could only claw part of it back. Under this weighting, most of your grade is already written by finals week.
Letter grade scale used by this calculator
For the most accurate result, enter the percentages shown in your gradebook. Letter inputs are estimates: a letter score uses the midpoint of its range, so a B counts as 84.5, and a letter target in the finals-week tab uses the bottom of its range, so A- means reaching at least 90. Schools vary, so percentages always win when you have them.
| Letter | Percentage |
|---|---|
| A+ | 97-100% |
| A | 93-96% |
| A- | 90-92% |
| B+ | 87-89% |
| B | 83-86% |
| B- | 80-82% |
| C+ | 77-79% |
| C | 73-76% |
| C- | 70-72% |
| D+ | 67-69% |
| D | 63-66% |
| D- | 60-62% |
| F | Below 60% |
Mode 02
What do you need on your semester final?
This is the December question, and it is what the second tab answers as a semester exam calculator: it takes your two quarter grades and your target, and returns the final exam score that gets you there. With an 88 and a 79 at 40% each, reaching an 85 semester grade takes a 91 on the final. Reaching a 90 would take a 116, which no exam allows, and the calculator says so honestly instead of letting you plan around a fantasy. If you want to compare every letter grade at once, the final exam calculator has a what-if table built for exactly that.
Reachable target
91%Needed on the final for an 85 semester grade, from an 88 and a 79 at 40/40/20.
Extra credit required
116%What a 90 semester grade would take from the same quarters. Not possible on the exam alone.
Mode 03
Semester grade without a final exam
Some classes skip the semester final, and mid-semester you may only have one quarter on the books. The third tab is a semester average calculator for those cases: enter the terms you have, and the math divides by the weight actually graded instead of punishing you with a zero for an exam that does not exist. Two quarters at 40% each with no final yet works out as (35.2 + 31.6) ÷ 0.80 = 83.5. Trimester schools work the same way with three terms.
Pick the right weights
High school and college semesters
The 40 40 20 grade calculator preset covers a common two-quarters-plus-final setup, but schools vary a lot: some districts run 45/45/10, some weight the final differently by course, and some drop it entirely. Check your student handbook or gradebook and use the custom weight fields when your school does its own thing. Many college courses skip quarters and weight a midterm and final inside one syllabus instead, which is a category problem: for that, use the weighted grade calculator and enter each category from the syllabus. For the quarter grades themselves, use the numbers your school reports, and this page does the rest.
Transparent by default
Methodology and citation
What the tool assumes
Term grades combine linearly by their stated weights. When entered weights total less than 100, the grade is normalized by the graded weight. Letter scores use range midpoints; letter targets use range bottoms. Required minimums are rounded upward.
What it does not assume
It does not predict curves, dropped quarters, exam exemptions, or district rounding rules. The result is a planning calculation, not a guarantee from your school.
Maintained by: DoMyHomework.co
Last reviewed: August 5, 2026
Cite this tool: DoMyHomework.co. “Semester Grade Calculator.” Updated August 5, 2026. https://domyhomework.co/tools/semester-grade-calculator/
Straight answers
Semester grade calculator FAQ
01 How do I calculate my semester grade with two quarters and a final?
Multiply each by its weight and add them. With an 88 and a 79 in the quarters at 40% each and an 85 final at 20%, that is 35.2 + 31.6 + 17 = 83.8.
02 What is a 40 40 20 grade calculator?
It is this calculation with a common high school weighting: each quarter counts 40% of the semester grade and the final exam counts 20%. It is the first preset in the tool above, but schools vary, so check your handbook.
03 How do I calculate my semester grade without a final?
Multiply each term grade by its weight, add them, and divide by the total weight you used. Two quarters at 40% each divide by 0.80. The no-final tab does this automatically.
04 What do I need on my final to get an A for the semester?
Subtract your banked quarter points from your target and divide by the final’s weight. The second tab calculates it instantly and tells you when a target is out of reach.
05 Do quarter grades or the final matter more?
Under 40/40/20, the quarters together are 80% of your grade, four times the final’s weight. The final matters most when the quarters are close to a letter boundary.
06 Is a semester grade the same as a semester GPA?
No. A semester grade is one class’s percentage. A semester GPA averages all your classes on a 4.0 scale using credit hours. A GPA calculator is a separate tool we’re building next.
07 How accurate is this semester grade calculator?
Exact for any class where the parts have fixed weights. It cannot predict district rounding rules, dropped scores, or a teacher’s curve, so your syllabus and gradebook stay the source of truth.