How this calculation works
A future attended class increases both the attended count and total completed count. Solve that changing-denominator inequality, then round up to a whole class. At an exact 100% target, a recorded absence prevents a finite perfect-attendance recovery.
For target p < 1: needed = ceil[(p × completed − attended)/(1 − p)], floored at zeroA worked example
With 16 attended out of 20 and a 90% target, 20 further consecutive attended classes produce 36/40 = 90%. Merely adding two to the attended count would ignore the growing denominator.
Good to know
Entered equal-weight counts and threshold only. No school policy, excused absences, subject weighting, rounding, future timetables or term resets. The completed count must be positive. A 100% threshold is treated exactly, not rounded from a near-perfect percentage.
Every future class changes the denominator too
Sixteen attended classes out of twenty completed classes is 80%. To reach 90%, adding two only to the attended count would give the misleading fraction 18/20. Two actual attended classes instead produce 18/22, because the completed count also increases.
Let x be the next consecutive attended classes and p the entered target as a fraction. The requirement is (attended + x)/(completed + x) ≥ p. At 16/20 and p = 0.9, solving gives x ≥ 20. Twenty consecutive attended classes produce 36/40 = 90%.
The calculator rounds a positive requirement upward to a whole class. A result of zero means the supplied history already meets the entered threshold. It does not mean the institution has accepted the attendance record, excused any absence or applied the same rule.
A final exam target solves a weighted-grade equation. Attendance target instead changes both attended and completed counts with every new class.
A current absence allowance is a different question
If the current ratio already meets the target, the tool also asks how many additional missed classes could be recorded while still meeting it at that moment. For 18/20 and an 80% threshold, two further absences give 18/22, still above 80%; three give 18/23, below it.
An exact 100% target has a special boundary. Once the supplied history contains an absence, any finite number of attended classes leaves that absence in the denominator. The ratio can approach 100% but cannot equal it in this fixed-history model. A rounded display must not be used to declare that boundary reached.
All classes here have equal weight, the history stays fixed and no future timetable is supplied. Subject-specific rules, excused absences, rounding and term resets require separate policy information. The final exam target calculator has a similar target-solving purpose but uses weighted grades rather than a growing class count.
A few questions, answered
Can I enter an institution’s attendance target?
Yes, as an arithmetic input. The calculator does not establish whether that threshold or counting rule actually applies to you.
Does the required run include future missed classes?
No. It is a consecutive attended-class requirement. If more classes are missed, update both counts and calculate again.
Why is there no finite answer for 100% after an absence?
Because the recorded absence remains in every future denominator while that history is kept. The tool does not silently round a near-perfect fraction to an exact target.