🎒Attendance Calculator

About this tool

Enter classes attended, classes held so far and the required percentage. You see your current attendance, and either how many classes in a row you need to reach the target or how many you can miss and stay above it. Add the classes left this term to see the best and worst possible finish and whether the target is still reachable.

The maths behind the 75% rule

Many universities and colleges — especially in India, where 75% is the usual minimum to sit exams — set a minimum attendance. Your attendance is attended ÷ held. To reach a target p by attending the next n classes, you need (attended + n) ÷ (held + n) ≥ p, which gives n ≥ (p × held − attended) ÷ (1 − p). With 42 of 60 classes (70%) and a 75% target, that is (45 − 42) ÷ 0.25 = 12 classes in a row. Going the other way, if you're above the target you can miss m classes while attended ÷ (held + m) ≥ p, so m ≤ attended ÷ p − held: 50 of 60 lets you miss 6 more at 75%. Knowing the classes left in the term shows the best achievable figure, which tells you early if the target is out of reach and it's time to talk to your department. Rules vary — some institutions count labs and lectures separately, round percentages, or condone medical absences — so check your handbook. The GPA calculator and the grade calculator handle marks, the percentage calculator does quick sums (Fractions, decimals and percentages: the same number three ways, and how to convert), and the pomodoro timer helps with the studying.

Frequently asked questions