# Grade calculator

> Grade calculator for weighted categories: your current course grade, and the score you need on the final exam or remaining work to reach a target.

Интерактивная версия: https://www.calcopenly.com/ru/everyday/grade-calculator
Тема: Повседневные калькуляторы

The current grade is the weighted average of the categories already scored: each score times its weight, added up and divided by the weight graded so far. The score needed on the remaining work is (target × total weight − weighted points earned) ÷ weight still to come.

With the defaults (homework 92 at 20%, quizzes 85 at 15%, a midterm of 78 at 25% and a final exam worth 40%), the current grade is 84.42%, a B. Reaching 90% needs 98.38% on the final; scoring 0% or 100% on it would leave the course at 50.65% or 90.65%.

Letter grades follow the College Board's general scale (A 90 and above, B 80–89, C 70–79, D 65–69, F below 65); your syllabus may use other cut-offs or plus and minus grades. Weights that do not add up to 100 are treated as shares of their total.

## Входные данные

- **Categories: name, weight %, score**: Leave the score off for work not yet graded. Scores can be percentages (92) or points (45/50).
- **Grade you want**

## Результаты

- Current grade — основной результат
- Letter grade now
- Needed on the remaining work
- Final grade with 100% on the rest
- Final grade with 0% on the rest
- Share of the course graded

## Формула

$$
\begin{gathered}\text{current} = \frac{\sum_{\text{graded}} w_i s_i}{\sum_{\text{graded}} w_i} \\ \text{needed} = \frac{T \sum w_i - \sum_{\text{graded}} w_i s_i}{\sum_{\text{remaining}} w_i}\end{gathered}
$$

## Примеры с решением

### Three graded categories, final worth 40%, target 90

- Categories: name, weight %, score: Homework, 20, 92 / Quizzes, 15, 85 / Midterm, 25, 78 / Final exam, 40
- Grade you want: 90%
- **Current grade: 84.42%**
- **Letter grade now: B**
- **Needed on the remaining work: 98.38%**
- **Final grade with 100% on the rest: 90.65%**
- **Final grade with 0% on the rest: 50.65%**
- Источник проверки: Python decimal: (20×92 + 15×85 + 25×78)/60 = 84.4167; (90×100 − 5065)/40 = 98.375

### Target out of reach

- Categories: name, weight %, score: Homework, 20, 92 / Quizzes, 15, 85 / Midterm, 25, 78 / Final exam, 40
- Grade you want: 95%
- **Needed on the remaining work: 110.88%**
- Источник проверки: Python decimal: (95×100 − 5065)/40

### Everything graded

- Categories: name, weight %, score: Coursework, 50, 90 / Exam, 50, 80
- Grade you want: 90%
- **Current grade: 85.00%**
- **Letter grade now: B**
- **Share of the course graded: 100%**
- Источник проверки: Hand calculation: (50×90 + 50×80)/100

### Weights that don't add to 100

- Categories: name, weight %, score: Labs 30 90 / Exam 30
- Grade you want: 80%
- **Current grade: 90.00%**
- **Needed on the remaining work: 70.00%**
- Источник проверки: Python decimal: (80×60 − 30×90)/30 = 70

### Points scores landing exactly on the A boundary

- Categories: name, weight %, score: Midterm, 25, 45/50 / Project, 25, 36/40 / Final, 50
- Grade you want: 80%
- **Current grade: 90.00%**
- **Letter grade now: A**
- **Needed on the remaining work: 70.00%**
- Источник проверки: Hand calculation: 45/50 = 36/40 = 90%; (80×100 − 4500)/50 = 70; College Board band A is 90–100

## Вопросы

### How do you calculate a weighted grade?

Multiply each score by its weight, add the results and divide by the total weight. Homework 92 at 20%, quizzes 85 at 15% and a midterm of 78 at 25% give (20 × 92 + 15 × 85 + 25 × 78) ÷ 60 = 5,065 ÷ 60 = 84.42%. Dividing by 60 rather than 100 gives the grade on the work marked so far.

### What score do I need on my final exam?

Needed = (target × 100 − weighted points so far) ÷ final exam weight, with weights in percent. With 5,065 weighted points from 60% of the course and a final worth 40%, a 90% course grade needs (9,000 − 5,065) ÷ 40 = 98.38% on the final. A result above 100% means the target is out of reach without extra credit.

### What percentage is an A?

On the College Board's general scale an A is 90–100%, a B 80–89%, a C 70–79% and a D 66–69%, and anything below 65% is an F; the calculator counts exactly 65% as a D. Many schools add plus and minus grades or set different cut-offs, so check your syllabus.

### What if the category weights don't add up to 100?

Each weight is treated as its share of the total. Labs worth 30 and an exam worth 30 add up to 60, so each counts for half the course. With 90 in labs and the exam still to come, an 80 overall needs (80 × 60 − 30 × 90) ÷ 30 = 70 on the exam.

### Can I enter scores as points instead of percentages?

Yes. Type 45/50 and it is converted to 90%. A midterm of 45/50 and a project of 36/40 are both 90%, so with each worth 25% the current grade is 90%, and an 80% course grade needs 70% on a final worth the remaining 50%.

### Насколько точен «Grade calculator»?

Точность зависит от введённых данных и допущений метода. Десятичная арифметика использует 50 значащих цифр, но оценки, численные методы и исходные данные могут быть менее точными; округление на экране не устраняет эти ограничения. Решённые примеры, проверенные по независимым источникам: 5. Например, «Three graded categories, final worth 40%, target 90» проверяется по источнику Python decimal: (20×92 + 15×85 + 25×78)/60 = 84.4167; (90×100 − 5065)/40 = 98.375.

### Откуда взята методика?

College Board BigFuture — How to convert your GPA to a 4.0 scale (letter bands); University of Michigan LSA — Grades and grading (weighted averages by credit).

## Источники

- [College Board BigFuture — How to convert your GPA to a 4.0 scale (letter bands)](https://bigfuture.collegeboard.org/plan-for-college/get-started/how-to-convert-gpa-4.0-scale)
- [University of Michigan LSA — Grades and grading (weighted averages by credit)](https://lsa.umich.edu/lsa/academics/lsa-academic-policies-and-procedures/grades-and-transcript-notations.html)