SBA score calculator: scale class and exam marks
Calculate weighted class assessment and exam scores with a free SBA calculator. Choose your school’s weights and follow a worked scaling example.
How to calculate a combined assessment score
First convert each raw score into a fraction of the available marks. Multiply that fraction by the percentage weight for that component, then add the two contributions. Class assessment and exam weights must total 100%.
Total = (class score ÷ class maximum × class weight) + (exam score ÷ exam maximum × exam weight)
Use the assessment weights approved for your level, subject and term. The values below illustrate the arithmetic; they are not a statement of a universal GES weighting or grading policy.
Calculate a weighted score
Replace the example values with your scores and your school’s approved weighting. Exam weight is 100% minus class assessment weight. This tool calculates in your browser; it does not save your scores.
Weighted total out of 100
Class: 28.80 + exam: 48.00 (exam weight: 60%)
Display rounded to two decimal places. Apply your school’s rounding and grade-band rules separately.
Worked example: different maximum marks
Suppose a teacher has a class assessment score of 72 out of 100 and an exam score of 64 out of 80. For an illustrative 40% class and 60% exam split:
- Class contribution: 72 ÷ 100 × 40 = 28.8.
- Exam contribution: 64 ÷ 80 × 60 = 48.
- Combined result: 28.8 + 48 = 76.8 out of 100.
Adding the raw marks first would give a different calculation and would not preserve the chosen 40:60 weighting. Scale each component separately before combining them.
Common SBA calculation mistakes
- Using the score as a percentage when the paper was marked out of 50, 80 or another total.
- Scaling a score twice after a spreadsheet or another tool has already weighted it.
- Treating a blank or missing assessment as zero without checking the school’s policy.
- Rounding component scores early, then using the rounded values for the total.
- Applying a grade band from a different class level, subject or assessment policy.
Questions about score scaling
Can I use a 50:50 split?
Yes. Set class assessment weight to 50 and exam weight becomes 50. Use this only when that split matches your school’s approved policy.
Does this calculate a GES grade or a BECE aggregate?
No. It calculates one weighted score out of 100. Grade bands, subject selection, aggregates and positions need their own applicable rules. Confirm those rules before assigning a grade.
What if I have several class assessments?
Combine them according to your school’s policy before entering the class score. If every raw mark carries equal weight, you can add the earned marks and maximum marks. If tasks carry different weights, calculate those contributions first.
After checking the totals, use the report-card checklist to review the rest of the report.