Attendance Calculator
Work out your attendance percentage against a required minimum, how many more classes you could miss, or how many you must attend to recover.
How it works
Attendance is attended ÷ held. The useful question is usually the next one: given where you are, how much slack is left. If you are above the requirement, you can miss classes until the ratio falls to it; if you are below, only attending future classes raises it.
Recovering is slower than falling. Each class missed costs you immediately, while each class attended only shifts the ratio slightly — which is why a shortage that took three weeks to build can take much longer to clear.
The formula
Attendance
percentage = (attended ÷ held) × 100
Classes you can still miss
floor(attended ÷ target − held)
Classes you must attend in a row
ceil((target × held − attended) ÷ (1 − target))
Worked examples
| Scenario | Working | Result |
|---|---|---|
| 45 of 60 attended, 75% required | 45 ÷ 60 | 75% — exactly at the line, 0 to spare |
| 50 of 60 attended, 75% required | floor(50 ÷ 0.75 − 60) | Can miss 6 more |
| 30 of 50 attended, 75% required | ceil((0.75×50 − 30) ÷ 0.25) | Must attend the next 30 |
When you'd use it
- Checking whether you can afford to miss a class
- Seeing how far behind the requirement you are
- Planning how to clear an attendance shortage
- Confirming eligibility to sit an exam
Common questions
How many classes can I miss and still keep 75%?
It depends on how many have been held so far, not just your current percentage. Enter both numbers and the tool works it out — at 50 of 60 attended you have six to spare, at 45 of 60 you have none.
Why does recovering take so many classes?
Because every class you attend also increases the total held. Missing one costs a full class against you; attending one only adds a fraction of a percent, so the climb back is much longer than the fall.
Does medical or duty leave count?
That is set by your institution, and policies vary widely. This calculator treats every class the same, so subtract any exempted classes from the total held before entering it if your rules allow that.
Are my grades sent anywhere?
No. Everything is calculated in your browser, so nothing you type is uploaded, logged or stored. There is no account and no record of what you entered.