How to Calculate Attendance Percentage

Attendance rules decide whether you can sit exams or pass a course. Learn to calculate your percentage and plan ahead.

The basic formula

Attendance % = (classes attended ÷ total classes) × 100

Count the classes you attended, divide by the total classes held, and multiply by 100. If you track absences instead, use: attended = total − absent.

Worked example

Example: 90 classes were held and you attended 82. Attendance = 82 ÷ 90 × 100 = 91.1%. If your school requires 75%, you are comfortably above it.

How many classes can I still miss?

To stay above a required percentage R over a total of T classes, you can miss at most:

Missable = T × (100% − R) ÷ 100

Example: 40 total classes, 75% required → you can miss 40 × 0.25 = 10 classes in the whole term.

Recovering after falling below

If your attendance already slipped, count how many classes in a row you must attend to climb back above the threshold. Every class you attend both raises the numerator and the denominator, so recovery gets easier as you go.

Classes to attend = (target% × total − attended) ÷ (100% − target%)

Example: 27 attended of 40 (67.5%), target 75%. Classes to attend = (0.75×40 − 27) ÷ 0.25 = 12 classes.

Frequently asked questions

What is a good attendance percentage?

Most schools expect 75–90% depending on the institution; high schools often flag attendance below 90%.

Do excused absences count?

Only if your school says so. Excused absences often don't hurt your grade but can still count against attendance policies — check your handbook.

Can attendance affect my grade even if I pass?

Yes — some courses grade participation, and many colleges require minimum attendance to sit exams.