Attendance Calculator: Your Percentage and the 75% Rule
This attendance calculator shows a student's attendance percentage and answers the real question behind it: how many classes can still be skipped, or how many must be attended in a row, to stay at 75% (or 80%, 85%, 100%). Add the number of classes left in the semester to see the best percentage still possible.
By Umer Sattar Updated 21 Oct 2026
84 of 120 classes attended
70% attendance
- Must attend in a row
- 24 classes
- Target
- 75%
- If you attend all left
- 77.5%
- Status
- Below target
Attendance percentage formula explained
Attendance % = classes attended ÷ classes held × 100 Classes to attend = ⌈ (target × held − attended) ÷ (1 − target) ⌉ Classes you can skip = ⌊ (attended − target × held) ÷ target ⌋ (target as a decimal, e.g. 0.75)
Example: 84 out of 120 classes is 70%. To reach 75% the student must attend ⌈(0.75 × 120 − 84) ÷ 0.25⌉ = 24 classes in a row. Another student with 100 out of 120 (83.3%) can skip ⌊(100 − 90) ÷ 0.75⌋ = 13 classes and still be at 75%.
Why do I need so many classes to climb back to 75%?
Every class you attend also adds one to the total. At 75%, each missed class needs three attended ones to balance it, so the gap closes slowly.
Attendance calculator for the 75% rule
Most Indian universities and boards ask for 75% attendance to sit end-semester exams, with condonation for genuine medical reasons at the principal's discretion, often down to around 65%. Hostel wardens in Hyderabad and Pune hear “just one more bunk” every week; this calculator gives the honest number before the shortage list comes out.
80%, 85% and 100% targets
- 80%: some autonomous colleges and professional programmes. Each missed class needs four attended to balance it.
- 85%: used by some private universities (KL University students can use the KL calculator with LTPS hours).
- 100%: possible only if no class has been missed; once one is missed, the calculator shows the best possible figure instead.
Monthly attendance tracking
For a monthly attendance check, enter the classes held and attended so far this month, or cumulatively for the semester, which is what shortage rules use. Teachers maintaining registers can use the same formula for a whole class by entering each student's numbers in turn.
No app needed: this works in any phone browser. Add it to the home screen from the browser menu for one-tap access before the next class.
Attendance Calculator: questions people ask
How do I calculate attendance percentage?
Attendance % = classes attended ÷ classes held × 100. For example, 90 of 120 is 75%.
How many classes can I skip and keep 75%?
Skippable classes = ⌊(attended − 0.75 × held) ÷ 0.75⌋. With 100 of 120 attended, that is 13 classes.
How many classes do I need to attend to reach 75%?
Classes to attend = ⌈(0.75 × held − attended) ÷ 0.25⌉. With 84 of 120, that is 24 classes in a row.
How does the 80 percent attendance calculation work?
Use 0.8 in the same formulas: to attend = ⌈(0.8 × held − attended) ÷ 0.2⌉, and to skip = ⌊(attended − 0.8 × held) ÷ 0.8⌋.
Can I get 100% attendance after missing a class?
No. A single missed class makes 100% impossible for that period.
Is there an attendance calculator app?
This page works like an app in any phone browser; add it to the home screen for quick access.