A semester grade in most US high schools is two quarter grades and a semester exam, combined by a fixed split that the district sets and the student rarely reads. The most common is 40/40/20. This page has the calculator with that split and the others, the formula, the exam score needed for every target, and the one rule that catches people: in some districts two failing marks fail the semester whatever the average.
Download the semester grade table (PDF) (the 40/40/20 formula, the exam score needed for every quarter average and target, the other splits and a planner; two pages, free).
The calculator
The 40/40/20 rule
Under the most common policy the semester grade is:
Semester = 0.40 x quarter 1 + 0.40 x quarter 2 + 0.20 x semester exam
It is the policy in Charlotte-Mecklenburg Schools (North Carolina), Howard County (Maryland, policy 8020) and Chariho (Rhode Island) among many others, and it is what a "two quarters and a final" course means unless the handbook says otherwise.
Worked example. Quarters of 84 and 88, semester exam 76: 0.4 x 84 + 0.4 x 88 + 0.2 x 76 = 33.6 + 35.2 + 15.2 = 84.00, a B on the plus-minus scale and a B on the 10-point scale. The quarters averaged 86.0; the exam at 76 pulled the semester down by 2.0 points, a fifth of the 10-point gap.
The other splits
| Split | Where it is used | Semester grade | What the exam can move |
|---|---|---|---|
| 40 / 40 / 20 | most districts (Charlotte-Mecklenburg, Howard County MD, Chariho RI) | 0.4 Q1 + 0.4 Q2 + 0.2 exam | a fifth of the gap between the exam and the quarter average |
| 45 / 45 / 10 | some districts, often as an option alongside 40/40/20 | 0.45 Q1 + 0.45 Q2 + 0.1 exam | a tenth of the gap |
| 50 / 50, no exam | courses with no semester exam, or exam-exempt students | 0.5 Q1 + 0.5 Q2 | nothing: the semester is the quarter average |
| 80 / 20, one body of work | districts that grade the semester as one 18-week gradebook plus the exam | 0.8 semester work + 0.2 exam | a fifth of the gap, as 40/40/20 |
| 80 / 20 with a state end-of-course test | courses with a state EOC exam counting 20 percent | 0.8 x (semester grades) + 0.2 EOC | the same arithmetic; the EOC score replaces the exam |
With the example quarters and exam, the 45/45/10 split gives 85.00 instead of 84.00: a lighter exam softens both a good and a bad exam day. The calculator's split menu switches the weights; a custom split can be typed in.
What you need on the exam
The exam score needed for a target semester grade under 40/40/20, by the average of the two quarters:
| Quarter average | For 95 | For 90 | For 85 | For 80 | For 75 | For 70 | For 60 |
|---|---|---|---|---|---|---|---|
| 95 | 95.0 | 70.0 | 45.0 | 20.0 | 0 (safe) | 0 (safe) | 0 (safe) |
| 92 | over 100 | 82.0 | 57.0 | 32.0 | 7.0 | 0 (safe) | 0 (safe) |
| 90 | over 100 | 90.0 | 65.0 | 40.0 | 15.0 | 0 (safe) | 0 (safe) |
| 88 | over 100 | 98.0 | 73.0 | 48.0 | 23.0 | 0 (safe) | 0 (safe) |
| 85 | over 100 | over 100 | 85.0 | 60.0 | 35.0 | 10.0 | 0 (safe) |
| 82 | over 100 | over 100 | 97.0 | 72.0 | 47.0 | 22.0 | 0 (safe) |
| 80 | over 100 | over 100 | over 100 | 80.0 | 55.0 | 30.0 | 0 (safe) |
| 78 | over 100 | over 100 | over 100 | 88.0 | 63.0 | 38.0 | 0 (safe) |
| 75 | over 100 | over 100 | over 100 | 100.0 | 75.0 | 50.0 | 0.0 |
| 72 | over 100 | over 100 | over 100 | over 100 | 87.0 | 62.0 | 12.0 |
| 70 | over 100 | over 100 | over 100 | over 100 | 95.0 | 70.0 | 20.0 |
| 65 | over 100 | over 100 | over 100 | over 100 | over 100 | 90.0 | 40.0 |
| 60 | over 100 | over 100 | over 100 | over 100 | over 100 | over 100 | 60.0 |
The rule the table shows: every point of target above the quarter average costs five points on the exam, and every point below it saves five. A student averaging 82 needs a 97 for an 85 and is safe for a 70 with a 22. Semester exams therefore decide letters at the margins (an 88 average reaching 90) and almost never rescue a semester (a 72 average reaching 80 needs 112).
The rule that is not arithmetic
Some districts add a condition to the formula. Charlotte-Mecklenburg's guideline, for example: if a student fails two of the three marks (the two quarters and the exam), the semester is failed regardless of the computed percentage. Others set a minimum exam score to pass, or exempt students with a high average and good attendance from the exam (in which case the split becomes 50/50). The calculator computes the average; the handbook has the conditions, and the week to read it is the first week of the semester.
The quarter grades themselves
A quarter grade is not an average over time; it is a weighted grade of the quarter's categories (homework, quizzes, tests, projects) in the syllabus's weights. The weighted grade calculator builds it. For what a single final counts for at the end of a full course, the final grade calculator. For the GPA the semester grades go into, the high school GPA calculator, where a semester course usually counts half a credit.
Using the number
In the last three weeks of the semester the two quarters are nearly fixed and the exam is the only variable, so the useful question is the exam score needed for each letter, read from the calculator's table. A student at an 88 average needs a 98 for an A- (90) on the plus-minus scale and a 78 to hold a B+; that student should study to hold the B+ and take the A- if it comes, which is a different week of work from "studying for the final".
Download the semester grade table (PDF) (the 40/40/20 formula, the exam score needed for every quarter average and target, the other splits and a planner; two pages, free).
Where to get help
A 1-on-1 online class with a tutor who holds a master's in mathematics and teaches the US curriculum, Algebra 1 to AP Calculus, chemistry and physics, at 7 am before school, after 4 pm and on weekend mornings, US time, for US$10 to $13 an hour: the grade worked out above read together in the free 30-minute first class, the category or the course where five more points cost least found, and the term spent on exactly that. How online tutoring from India to the USA works, or the 1-on-1 online tutoring page.
Questions parents ask
1How is a semester grade calculated?
2What do I need on the semester exam?
3Is the semester grade just the average of the two quarters?
4Can I fail the semester with a passing average?
5How do I calculate a quarter grade?
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