Grade Calculator
| Assignment / Category | Score Earned | Total Points | Weight (%) | |
|---|---|---|---|---|
Grade Calculator
A grade calculator converts raw scores or weighted category results into a percentage and letter grade, letting you track academic performance at a glance.
Conversion Formula
Simple mode: Grade % = (Sum of Scores Earned ÷ Sum of Total Points) × 100. Weighted mode: Grade % = Sum(Category Score% × Category Weight) ÷ Sum(Weights). Both formulas then map the percentage to a letter grade using standard cutoffs.
Step-by-Step Examples
Simple mode - Quiz: 18/20, Homework: 45/50, Test: 78/100 = 83.24% - B
Total earned = 18 + 45 + 78 = 141. Total possible = 20 + 50 + 100 = 170. Grade = 141 ÷ 170 × 100 = 82.94% ≈ 83.24% (B).
Weighted mode - Homework: 90/100 (weight 20%), Midterm: 74/100 (weight 40%), Final: 88/100 (weight 40%) = 83% - B
Weighted sum = 90×20 + 74×40 + 88×40 = 1800 + 2960 + 3520 = 8280. Divide by total weight 100 = 82.8%, rounds to 83% (B).
Simple mode - Essay: 88/100, Presentation: 42/50, Lab: 95/100 = 90.4% - A-
Total earned = 88 + 42 + 95 = 225. Total possible = 100 + 50 + 100 = 250. Grade = 225 ÷ 250 × 100 = 90% (A-).
History
Letter grades were introduced in the United States in the late 19th century, with Harvard adopting the A-F scale around 1884. Before standardized letter grades, teachers used written descriptions of student performance. Weighted grading systems became common in higher education during the 20th century to reflect the varying importance of different assessments.
Common Use Cases
- Tracking current standing mid-semester
- Projecting final grade before finals week
- Comparing impact of missing assignments
- Understanding how each category affects your overall grade
Frequently Asked Questions
What is the difference between simple points and weighted categories?
Simple points adds up all earned points and divides by total possible points. Weighted categories assigns each category a percentage weight (e.g., 40% exams, 30% homework), so each category's raw score is scaled by its importance before averaging.
Do my category weights have to add up to 100%?
No. The calculator divides by the sum of the weights you enter, so partial or unequal totals still produce a correct weighted average. If you enter 40% and 30%, it computes (40+30=70) as the denominator.
How do I calculate my standing before the final exam?
Enter all graded assignments or categories so far. The result shows your current grade. To project your final grade, add a final-exam row with an estimated score and its weight.
Which letter grade scale does this calculator use?
It uses the standard plus/minus scale: A (93-100), 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 (60-66), F (below 60). Some schools use different cutoffs.
What if I receive extra credit that pushes my score above the total points?
Enter the extra credit in the score field so it exceeds the total. For example, score 105 out of 100. The calculator handles scores above 100% correctly in simple mode, and the weighted mode treats it as a category score above 100%.