Attendance calculator — your percentage, classes to attend and classes you can miss

How to use the attendance calculator

1. Enter Classes attended and Classes held so far. Use whole classes.
2. Enter Required attendance in percent, the minimum your school, college or course sets.
3. If you know it, enter Total classes this term (optional) to get a plan for the rest of the term.
4. Read Current attendance, Classes to attend in a row and Classes you can miss. The message underneath tells you where the next classes will leave you.

What it does and when to use it

When attendance is below the minimum, the real question is how many classes it will take to get back. When it is above, the question is how much room you have. Being off by one class can matter. The calculator gives the exact whole number both ways.

Use it before a planned absence, after an illness, or when a shortage notice arrives. If the shortage might affect your marks, the final grade calculator shows what you need on the final, and the revision timetable planner helps you catch up on missed topics. The exam countdown shows how many days remain.

How it works

With a attended, h held and r the required share (75% = 0.75):

• Current attendance = a ÷ h × 100.
• Classes to attend in a row: the smallest whole number n with (a + n) ÷ (h + n) ≥ r, which is n = (r × h − a) ÷ (1 − r), rounded up.
• Classes you can miss: the largest whole number m with a ÷ (h + m) ≥ r, which is m = a ÷ r − h, rounded down.

For the term plan, the classes you need overall are r × term total, rounded up. Subtract what you have attended to get the classes you must still attend; the rest of the remaining classes can be missed. If you would need more classes than remain, the table says it is not reachable.

Worked examples

Below the minimum. 42 of 60 classes with 75% required is 70%. The tool says: “Attending the next 12 classes brings you to 75% (54 of 72).” With a 90-class term, you need 68 in total, so you must attend 26 of the last 30 and can miss 4.

Above the minimum. 52 of 60 is 86.67%. You could miss the next 9 classes in a row and stay at 75%; a 10th would drop you below. Over the whole 90-class term you can miss 14 of the 30 left, as long as you attend the other 16.

Not reachable this term. 30 of 50 with 85% required needs 84 classes in a row, but a 60-class term has only 10 left. You would need 51 in total, and the table shows “21 (more than remain — not reachable)”.

Limits and tips

• The tool rounds class counts to whole numbers and does not check your institution’s rounding rule (for example whether 74.5% counts as 75%).
• Late arrivals, half-day sessions and leave are not handled; count them the way your institution does.
• Recalculate after every week so you notice a slide early.