Check your attendance against the 75% rule

The 75% rule — why it exists

Most Indian universities, and CBSE for board exam eligibility, require at least 75% attendance. Fall below it and you can be barred from sitting the exam, no matter how well you know the subject. The rule exists because attendance is treated as part of the course, not just a record. Check your own university's exact threshold — some set 80% or 85%.

How many classes can you miss?

The number you can still miss is floor(attended ÷ target − total). At 55 out of 60 classes (91.7%) with a 75% target, that is floor(55 ÷ 0.75 − 60) = 13 classes. At exactly 75% — say 30 out of 40 — the answer is zero: miss one more and you drop below the line. The tool does this math for you and shows the drop if you miss the next class.

How many in a row to recover?

If you are below target, the classes you must attend in a row are ceil((target × total − attended) ÷ (1 − target)). At 42 out of 60 (70%) with a 75% target, that is ceil((45 − 42) ÷ 0.25) = 12 classes in a row. One absence costs about three attended classes to undo, because every attended class only nudges the ratio a little. Start the recovery now — the longer you wait, the longer the streak.

The tool also shows the 'miss the next class' warning: at 42 out of 60, one more absence drops you to 68.9%.

Labs count more than lectures

A 3-hour lab session usually counts as 3 periods, not one class — missing a lab hurts three times as much as missing a lecture. Enter your labs separately and the tool weights each lab session as 3 periods in the same calculation. If your college counts labs differently, check the rule and adjust.

Multiple subjects — the overall is a ratio, not an average

Overall attendance is total attended divided by total held across all subjects. A 90% in one subject does not cancel a 50% in another the way a simple average would — the subject with more classes weighs more. Paste one line per subject (Subject, attended, total) and the tool shows each subject and the true overall figure.

Condonation — the 65–75% band

Many universities let you apply for condonation if your attendance is between 65% and 75% — usually with a medical certificate and a fee. Below 65% you are usually detained for the semester, whatever the reason. Condonation is not automatic: it is an application your department and university must approve. Talk to your department early, not after the list is published.

Common mistakes

The most common mistake is averaging subject percentages instead of using the total ratio. The second is forgetting labs, which weigh three times a lecture. The third is counting holidays or cancelled classes as held — only classes that actually took place count in the total. And the fourth is assuming one absence is harmless: at 70% attendance it costs you three attended classes to recover.