Attendance calculator
Enter the classes held so far, the ones you attended and your target. The calculator shows your attendance and how many more classes you can skip, or have to attend, to stay at or above the target.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter the classes held so far and the classes you attended.
- Enter your target, for example 75.
- Optionally enter the classes left in the term to get an end-of-term answer.
How it works
Attendance is attended divided by held. Above the target, the number of classes you can skip in a row is the largest whole m with attended / (held + m) ≥ target. Below it, the number to attend in a row is the smallest whole n with (attended + n) / (held + n) ≥ target. For the end of the term, the final attendance is (attended + attended-from-remaining) / (held + remaining), and the most you can miss is attended + remaining − target × (held + remaining).
Worked example
You attended 32 of 40 classes (80%) and the target is 75%:
- 32 / 0.75 = 42.67, so you can miss 2 more in a row: 32 / 42 = 76.2%, but 32 / 43 = 74.4%;
- with 20 classes left, the term has 60 classes, 45 must be attended, so you need 13 of the 20 and can miss 7.
Tips
- Check whether your school counts late arrivals or excused absences as present before relying on the result.
- Tracking attendance weekly is easier than finding out at the end that the target is out of reach.
Frequently asked questions
How is attendance percentage calculated?
Divide the classes you attended by the classes held and multiply by 100. Attending 32 of 40 classes is 32 / 40 = 80%.
How many classes can I miss and still keep 75%?
With attended classes A and held classes H, you can miss m more classes in a row while A / (H + m) stays at or above the target. The calculator rounds down to a whole number, because a part of a class cannot be missed.
What if I am already below the target?
Then the result shows how many classes you must attend in a row, without missing any, to climb back. Attending n more classes gives (A + n) / (H + n). The number rises quickly when the target is high.
What does the end-of-term result tell me?
If you enter how many classes are left, it works out how many of those you can miss, and the number you need to attend, so that your final attendance is at or above the target. It says so when the target is out of reach even if you attend every remaining class.