Attendance Shortage Calculator
Enter classes attended, classes held and your target attendance percentage to find the minimum number of classes you need to attend consecutively — or how many you can afford to miss.
How It Works
Current attendance is the share of held classes you attended:
Current Attendance = (Classes Attended ÷ Classes Held) × 100
If you're below target, the calculator solves for the smallest whole number of additional classes (x) you'd need to attend in a row so that (Attended + x) ÷ (Held + x) ≥ Target. If you're already at or above target, it instead estimates how many more classes you could miss in a row while staying at or above that target.
Example
Attended 60 of 80 classes with a 75% target: current attendance is exactly 75%, so 0 additional classes are required. But with 60 of 90 classes at the same 75% target, current attendance is only 66.67%, so several more consecutive classes are needed to reach 75%.
Frequently Asked Questions
- How is this different from the Attendance Calculator?
- The Attendance Calculator gives you a quick percentage with an optional goal check. This calculator focuses specifically on the shortage scenario — precisely how many classes you need, or can miss, to hit a target.
- Why do I need to attend classes 'consecutively' for the estimate to work?
- The calculation assumes every future class in the window you're solving for is attended (or missed). If your actual attendance is mixed, recalculate with updated numbers as your semester progresses.
- What's a typical target attendance percentage?
- Many schools and colleges require around 75%, but this varies by institution and course — always check your own attendance policy.
- What if I can never reach my target attendance this term?
- If too many classes have already passed, no number of future classes may be enough to reach a high target within the remaining term — in that case, talk to your institution about their policy.