The formulas
Points: new grade = (earned + new earned) ÷ (possible + new possible)Weighted: new grade = current × (1 − w) + score × wWorked examples
Points: you have 170 out of 200 points (85%). Scoring 45 out of 50 on the next assignment gives 215 out of 250, which is 86%. Your grade goes up 1 point.
Weighted: you have 88% and the next test is worth 15% of your grade. A 70% on it gives 88 × 0.85 + 70 × 0.15 = 85.3%, a 2.7-point drop.
Common questions
- How much will one test change my grade?
- It depends on how much the test is worth compared with everything already graded. A 50-point test added to 200 points of earlier work moves your grade far more than the same test added to 900 points.
- Should I use points or weight?
- Use points if your teacher adds up points across the whole class. Use weight if your syllabus says something like 'tests are 40% of the grade' and you know what share of your grade this one assignment is.
- Why did a good score barely raise my grade?
- Late in the term, a lot of work is already counted, so each new assignment is a smaller share of the total. Early in the term, single assignments swing your grade more.