Enter completed classes
Enter attended and conducted class counts. Use one consistent unit: classes, not a mixture of classes and hours.
Attendance Calculator
Calculate your current class attendance, how many consecutive classes you need to attend, and how many you can miss while meeting an entered target.
Workspace
Use the tool below. Your inputs stay local when the tool supports browser-only processing.
Last reviewed: · Testing methodology
Workflow
How to use the Attendance Calculator
Set your target
Enter the percentage that applies to you. Add remaining classes only if you know the schedule; no university threshold is assumed.
Read the scenario
Calculate to see the current fraction, consecutive attendance needed and maximum extra absences. A target may be impossible within the remaining schedule.
How this tool works
Current percentage is A/T × 100. For a target fraction q between 0 and 1, catch-up is max(0, ceil((qT − A)/(1 − q))). When already at target, missable classes are floor(A/q − T). Zero conducted classes and 0%/100% targets use explicit boundary rules.
- Engine: Integer class counts and exact basis-point threshold arithmetic
- Supported input: whole attended and conducted class counts, 0–100% target with up to two decimals, optional whole remaining-class count
- Output: attendance percentage, class counts and formula breakdown
- Input
- 30 attended, 50 conducted, target 75%
- Output
- 60% current attendance; 30 consecutive attended classes reach 60/80 = 75%.
Limits, edge cases, and troubleshooting
Use the remaining-class field to distinguish eventual mathematical catch-up from what is possible this term. With only 20 classes left in this example, the maximum is 50/70 = 71.4286%.
- Class-count inputs are limited to one billion to keep results within supported arithmetic bounds.
- No university rules, excused-absence policy or subject eligibility are inferred.
- Catch-up assumes every additional class is attended; display rounding never determines eligibility.
When to use another workflow
Use the institution's official attendance portal when hours, excused sessions, practicals or separate subject requirements affect eligibility.
| Option | Best for | Trade-off |
|---|---|---|
| This browser tool | Quick, private, one-off work | Limited by browser memory and the documented feature set |
| Desktop or command-line tool | Batch jobs and repeatable automation | Requires installation and setup |
Verification
Implementation checked on 2026-09-16. Unit tests and local browser checks covered 30/50 at 75% (30 catch-up classes), zero conducted classes, 0% and 100% targets, invalid counts and a finite remaining schedule. Narrow layouts and a keyboard-only calculation were checked.
Read the testing methodologyAttendance Calculator — Frequently Asked Questions
Is 75% a universal attendance requirement?
No. The example uses 75% only to demonstrate the arithmetic. Enter your own target and check subject-specific, excused-absence and eligibility rules with your institution.
Can I recover exact 100% after missing a class?
No finite number of additional attended classes removes an earlier absence from the conducted total. If every conducted class was attended, catch-up is zero. If no classes were conducted, one attended class establishes a percentage.