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Attendance Calculator

Check your class attendance percentage and plan the rest of the term. Enter how many classes have been held and how many you attended, set the required percentage, and see how many classes you need to attend in a row to reach it, or how many you can safely miss.

%

Shows how many of them you must attend.

Enter your values to see the result.
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How to use the Attendance Calculator

  1. Enter the classes held so far and the number you attended.
  2. Set the required attendance, for example 75%, or tap a preset.
  3. Optionally enter the classes left in the term to see what you need overall.
  4. Press Calculate attendance to see your percentage and how many classes to attend or how many you can miss.
  5. Use the table to see your attendance after each of the next classes if you attend or miss them.

Attendance formulas

  • Attendance % = attended ÷ held × 100
  • Classes needed to reach target T% = ⌈(T × held − 100 × attended) ÷ (100 − T)⌉
  • Classes you can miss and stay at T% = ⌊(100 × attended − T × held) ÷ T⌋
  • Minimum of R remaining classes to attend = ⌈T × (held + R) ÷ 100 − attended⌉

⌈ ⌉ means round up and ⌊ ⌋ means round down, because you can only attend whole classes.

Classes needed to reach 75% (attending every class)

Classes heldAttendedCurrent %Classes needed for 75%
402870.0%8
503570.0%10
604270.0%12
603965.0%24
805265.0%32
1006060.0%60

Falling 10 points below a 75% target means you need as many extra classes as 40% of those already held. Staying a few classes above the minimum gives you a buffer for illness or emergencies.

Frequently asked questions

How do I calculate attendance percentage?

Divide the classes you attended by the classes held and multiply by 100. For example, 42 classes attended out of 60 held is 42 ÷ 60 × 100 = 70%.

How many classes do I need to attend to reach 75%?

Use x = (0.75 × held − attended) ÷ (1 − 0.75), rounded up. With 42 out of 60 classes, x = (45 − 42) ÷ 0.25 = 12, so you need to attend the next 12 classes in a row to reach 54 out of 72, which is exactly 75%.

How many classes can I miss and keep 75% attendance?

Use y = attended ÷ 0.75 − held, rounded down. With 50 out of 60 classes attended, y = 66.67 − 60 = 6.67, so you can miss 6 classes in a row and still be at 50 ÷ 66 = 75.76%.

Why do I need so many classes to recover?

Every class you attend also increases the number of classes held, so each one only lifts your percentage a little. The further you are below the target, and the higher the target, the more classes you need. That is why catching up early is much easier.

Can I reach 100% attendance after missing a class?

No. Once you have missed even one class, your attendance can get closer and closer to 100% but never reach it, because the missed class always stays in the total.

Does the calculator know my college's attendance rules?

No. It does the math for any target you enter. Rules on medical leave, condonation, separate lab and theory attendance or rounding differ between schools and universities, so check your institution's policy.

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