The attendance formula
(Classes attended ÷ Classes held) × 100“Classes held” means sessions actually conducted, not every class that originally appeared on a timetable. “Classes attended” is the number for which you received attendance credit.
Worked examples
Example: exactly 75%
If 40 classes were held and you attended 30, the result is 30 ÷ 40 × 100 = 75%.
Example: below target
If you attended 35 of 50 classes, you have 70%. To reach 75%, you must attend 10 consecutive future classes: 45 ÷ 60 = 75%.
Example: safe absence buffer
If you attended 54 of 60 classes, you have 90%. At a 75% target, you can miss 12 future classes and remain exactly at 75%: 54 ÷ 72 = 75%.
Common mistakes
- Dividing missed classes by total classes instead of attended classes.
- Counting cancelled sessions as held classes.
- Rounding too early in a multi-step calculation.
- Assuming every institution rounds 74.5% upward.
- Ignoring separate lecture and laboratory requirements.
Frequently asked questions
Can attendance go back up quickly?
Recovery becomes slower as more classes are held because each new class has less influence on the full total.
Is 75% a universal rule?
No. Requirements vary by institution, program, subject, and class type. Enter the target shown in your official policy.
Should I trust a calculator over the student portal?
No. Use the calculator for planning and the official portal or department record for final decisions.