How the Grade Calculator Works
The grade calculator on this page answers three different questions students ask in different orders during a semester. The first — what is my current grade? — is what the Course Grade tab does. You add every assignment, midterm, quiz, and project with the score you got and how much it counted toward the final grade, and the calculator weighs them together into one overall percentage and the matching letter grade. The second — what do I need on the final to land my target? — is what the Final Exam Needed tab does. You enter your current grade, the final's weight as a percentage of the course, and what overall grade you want, and it returns the exact score you need on the final. The third — is 87 a B+? — is what the Letter Grade Scale tab does, with a reference table mapping percentages to letters and GPA values.
Every input field accepts both percentages and letter grades. Type 87 or B+ — either works. Internally, letter grades convert to percentages using the midpoint of each tier (A- becomes 91, B+ becomes 88, F becomes 30) so weighted averages stay accurate.
Course Grade Mode — Weighted Average Across Assignments
Courses don't usually weight every assignment equally. A final exam might be worth 30% of your grade while individual homework assignments are worth 2-5% each. To get a true overall grade, every score has to be weighted by how much it matters. The Course Grade mode handles that math.
Add a row for each item in your syllabus's grading breakdown. The label is just for your reference — the calculator only uses the grade and weight. Most courses publish a grading rubric like this:
| Component | Weight |
|---|---|
| Homework (avg) | 20% |
| Quizzes (avg) | 10% |
| Midterm 1 | 15% |
| Midterm 2 | 15% |
| Final exam | 30% |
| Participation | 10% |
For homework and quizzes, plug in your average score across all of them and use the category's full weight. You don't need a separate row for each individual quiz unless your instructor weights each one differently.
Final Exam Mode — Reverse Calculation
This mode is the most-asked grade question on the internet for a reason: in the last weeks of a semester, students need to know what's still mathematically possible. The formula is straightforward algebra:
required = (target − current × (1 − weight)) / weight
where weight is the final exam's share of the overall grade, expressed as a decimal (0.30 for a 30% final). Plug in numbers and the answer falls out. The calculator shows it color-coded so you can read the verdict at a glance: green if you can hit the target with a reasonable score, gold if you'd need extra credit on the final, coral if it's not achievable through the final alone.
Below the verdict, a what-if grid shows the overall grade you'd land at six common final-exam scores (50, 60, 70, 80, 90, 100). The cells turn green when the projected overall grade meets your target. This is useful when the required score is borderline — you can see exactly how much room you have if you score a 75 instead of a 70.
Worked Example
required = (88 − 82 × 0.7) / 0.3 = (88 − 57.4) / 0.3 = 30.6 / 0.3 = 102%
You'd need to score 102% on the final — meaning a perfect score plus extra credit. The verdict zone turns gold; the what-if grid shows that scoring 90 would land you at an 84.4% (still a solid B), and scoring 100 lands you at 87.4% (just under your B+ target). You can adjust your goal accordingly.
Letter Grade Scale Reference
The third tab is a static lookup table. Most US colleges and high schools use a standard scale where A starts at 93 (or 90 for an A-), B at 83, C at 73, D at 63, and F at 0. The table also shows the GPA value each letter is worth on the standard 4.0 scale — useful when computing your cumulative GPA on our GPA Calculator.
Some institutions use stricter scales (A starts at 94 or 95, F at 65 instead of 60). If your syllabus uses a non-standard scale, the percentages are still correct — just convert using your school's specific letter thresholds, not the table here. The calculator's percentage outputs work regardless of which letter scale you use.
Common Pitfalls When Calculating Grades
Forgetting non-graded participation points. Many courses include attendance, in-class participation, or discussion-board contributions in the weight breakdown. These are real points. Check your syllabus for them.
Lowest-score-dropped policies. Some courses drop your lowest quiz or homework score. The calculator doesn't know about this — if your syllabus says "lowest two quizzes dropped," compute your average across the surviving quizzes only and enter that.
Curves and grade adjustments. Curves are applied at the instructor's discretion at the end of the term, not automatically. The calculator gives the raw weighted-average answer; if your course is curved, your final grade may be higher than what shows here.
Final exam replacement rules. A small but growing number of courses let the final exam replace your lowest midterm score. If yours does, the math gets more complex — this calculator gives the straight weighted-average answer, which is the conservative case (worst-case if the replacement doesn't help you).
What the Calculator Doesn't Do
It doesn't model curves, extra credit beyond the final exam, lowest-grade-dropped rules, or attendance bonuses. It doesn't compute cumulative GPA across multiple courses (use our GPA Calculator for that). It doesn't track grades over time or save your assignment list across visits — everything stays in your browser session and disappears when you close the tab. We don't store your grades on our servers; we don't have an account system; we don't email you. The whole calculation runs in your browser.
If you want to do raw percentage math without weighting (just averaging numbers), our Percentage Calculator and Average Calculator are simpler tools for that.
Why Three Modes on One Page
Search "grade calculator" and the top result will probably be a page with multiple modes. That's because students arrive with different questions throughout the semester — sometimes they want to know their current grade, sometimes they want to know what's left to fight for, sometimes they're just checking what counts as a B+. Putting all three on one page means you don't have to bookmark three different tools. The mode you're using saves to the URL (#course / #final / #scale), so you can deep-link to a specific calculator if you want.
One page, three calculators, no sign-up. Open and use.