Attendance calculator

Attendance is a plain ratio: classes you attended divided by classes that were held. The two useful questions are what happens to that ratio when you add absences, and what happens when you add attendances.

Classes you can still skip. Skipping adds to the bottom of the fraction but not the top, so your percentage falls. The largest number of skips that keeps you legal is:

The result is rounded down because half a class does not exist, which means the answer errs on the safe side rather than the flattering one.

Classes you must attend. Attending adds to both the top and the bottom, so your percentage rises, but slowly. The smallest unbroken run that gets you to the threshold is:

This is why recovering from a bad start is so much harder than protecting a good one. At a 75% requirement, every class you miss costs three classes of perfect attendance to undo.

Say 40 classes have been held and you attended 30. That is 75% exactly, so you can skip zero more. If you attend the next 4 without missing any, you are at 34 of 44, which is 77.3%, and the calculator will then tell you that you can afford to miss 1.

Now say you attended only 20 of those 40, which is 50%. To reach 75% you have to attend the next 40 classes in a row, ending at 60 of 80. Missing a single class in that run pushes the requirement higher again. The gap between 50% and 75% is not 25 classes, it is 40.

Why is 75% attendance the number everyone talks about?

Most Indian universities and affiliated colleges set a minimum attendance requirement for exam eligibility, and 75% is the most common figure. It is a rule set by each institution, not a national law, so some departments use 80%, some allow a lower figure with a medical certificate, and some count practicals separately. The calculator defaults to 75% and lets you change it to whatever your own handbook says.

How many classes can I skip if I am at exactly 75%?

None. At exactly the threshold, the next class you miss puts you below it. The calculator returns zero in that case rather than rounding up to a friendlier number.

How is the number of classes I can skip calculated?

It solves attended divided by held plus skipped, greater than or equal to your threshold, for the largest whole number of skips. Because you cannot skip part of a class, the result is rounded down, so the answer is always safe rather than optimistic.

Does this account for classes that have not happened yet?

The skip answer assumes the only classes left to count are the ones you skip. If your semester has more classes scheduled after that, attending them will push your percentage back up, so treat the skip number as the worst case rather than a hard limit.

My college counts each subject separately. Does that matter?

Yes, and it matters a lot. If attendance is tracked per subject, run the calculator once per subject with that subject's own attended and held counts. An overall average can hide one subject sitting below the line.

Is this attendance calculator free?

Yes. It runs entirely in your browser, there is no account and no signup, and nothing you type is sent anywhere.