80% Attendance Calculator
Enter your classes held and attended to see whether you meet the 80% attendance requirement, how many classes you can still miss, or how many you must attend in a row to get back to 80%.
You are above 80%. You can miss up to 6 of the next classes and still be eligible.
Step-by-step solution
- Current attendance = (45 ÷ 50) × 100 = 90%
- To stay at 80%: 45 ÷ (50 + y) ≥ 0.8
- y ≤ 45 ÷ 0.8 − 50 = 6.25 → you can miss 6 classes
80% attendance ready reckoner
Minimum classes you must attend, and the most you can miss, to be at exactly 80% after a given number of classes.
| Classes held | Must attend (min) | Can miss (max) |
|---|---|---|
| 10 | 8 | 2 |
| 20 | 16 | 4 |
| 30 | 24 | 6 |
| 40 | 32 | 8 |
| 50 | 40 | 10 |
| 60 | 48 | 12 |
| 80 | 64 | 16 |
| 100 | 80 | 20 |
| 120 | 96 | 24 |
| 150 | 120 | 30 |
| 200 | 160 | 40 |
The formula
Attendance % = attended ÷ held × 100. To stay at 80%, you can miss floor(attended ÷ 0.8 − held) more classes. If you are below 80%, attend ceil((0.8 × held − attended) ÷ 0.2) classes in a row.
Frequently asked questions
How many classes can I miss with a 80% attendance requirement?
Out of every 100 classes you can miss at most 20. For your own numbers, enter them in the calculator above — it accounts for classes already held.
How do I calculate if I have 80% attendance?
Divide classes attended by classes held and multiply by 100. If the result is 80 or more, you meet the requirement.
I am below 80%. How many classes must I attend?
Use (0.8 × held − attended) ÷ (1 − 0.8) and round up. For example, with 42 of 60 classes you need to attend the next 30 classes without a break.