Attendance calculator: how many classes can you miss?

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How attendance percentage works

Your attendance percentage is the classes you attended divided by the classes held, times 100. If 60 classes have been held and you attended 42, your attendance is 42 ÷ 60 × 100 = 70%.

Count in the same unit your college uses. Some colleges count every period or hour, others count whole working days. Mixing the two gives the wrong answer.

How many classes do you need to attend?

When you are below the minimum, every class you attend raises both numbers by one. In the example above, reaching 75% means finding the smallest number of classes x where (42 + x) ÷ (60 + x) is at least 0.75. That works out to 12 classes in a row, which gives 54 out of 72, exactly 75%.

The general formula, rounded up to the next whole class, is:

classes needed = (required% × held − 100 × attended) ÷ (100 − required%)

How many classes can you miss?

When you are above the minimum, each class you miss adds one to the classes held but nothing to the classes attended. With 50 out of 60 (83.3%), you can miss 6 more classes: 50 out of 66 is 75.8%, but 50 out of 67 drops to 74.6%. The formula, rounded down, is:

classes you can miss = (100 × attended ÷ required%) − held

Before you rely on the number

• Many colleges ask for 75% attendance to sit the semester exam, but the exact rule, and whether medical leave or on-duty days count, depends on your college’s regulations. Check with your department.
• Use the attendance figures your department records, not your own count, when the two disagree.
• Plan ahead with the calendar. The 2026–27 holidays and important dates show how many working days are left before exams.