Attendance Calculator — Check Classes Needed or Safe to Miss
Enter the number of classes held and the number attended to calculate your current attendance percentage. Set a requirement such as 75% to see how many consecutive classes you need to attend, or how many future classes you may be able to miss while remaining at or above the target.
Attendance percentage formula
Attendance percentage = classes attended ÷ classes held × 100 To find consecutive attended classes needed for a target t, where t is written as a decimal: classes needed = ceiling((t × classes held − classes attended) ÷ (1 − t)) To estimate future classes that may be missed while maintaining the target: classes that may be missed = floor(classes attended ÷ t − classes held) A zero result means no class can currently be missed.
Worked example for 75% attendance
If 80 classes have been held and 56 were attended: 56 ÷ 80 × 100 = 70% For a 75% target: (0.75 × 80 − 56) ÷ (1 − 0.75) = 16 The student needs to attend the next 16 consecutive classes to reach 75%, assuming every new class counts equally.
Example of classes that may be missed
If 80 classes have been held and 64 were attended, current attendance is 80%. floor(64 ÷ 0.75 − 80) = floor(5.33) = 5 The student could miss five additional equally weighted classes and remain at or above 75%.
Important limitations
Universities may calculate lectures, laboratories and tutorials separately; apply course-level rather than overall attendance; round differently; exclude cancelled classes; or require medical documentation. An attendance estimate does not confirm official exam eligibility.
FAQs
How many classes do I need to attend to reach 75%?
The number depends on classes held and attended. Enter both figures and set the target to 75%.
Can I reach 75% by attending every remaining class?
Use the optional remaining-classes field. If the projected final percentage remains below 75%, that target is not mathematically reachable under the entered schedule.
Does one missed lab count the same as one lecture?
Not always. Calculate them separately when the institution tracks or weights them separately.
Does the calculator approve an attendance shortage?
No. Only the institution can apply condonation, medical or other exceptions.