How to use the attendance percentage calculator
- Enter the days attended and the days held so far, counting every day or class that has already happened.
- Optionally enter the attendance you need as a percent and the days in the whole term.
- Read your attendance rate and absence rate.
- If you entered a requirement and a term length, read the most days you can miss in the term and how many you can still miss.
Formula
Attendance rate = days attended / days held x 100
Days you must attend in the term = round up (required % x term days / 100)
Most days you can miss = term days - days you must attend
Days you can still miss = most days you can miss - days already missed
Rounding up the days you must attend is what makes the answer safe: a part of a day cannot count.
Eighty-two days out of ninety
A student who attended 82 of 90 days has an attendance rate of 82 / 90 x 100 = 91.11%, and has missed 8 days. If the term is 180 days and 90% is needed, they must attend 162 days, so they can miss 18 days in all, which leaves 10 more. They must attend 80 of the 90 remaining days.
In a 40 day term that needs 92.5%, the student must attend 37 days, so 3 absences are allowed. If a student has 18 of 20 days at 95% in a 20 day term, they must attend 19, so the limit is already passed.
Counting attendance the way your rule does
Schools, programs and employers count attendance differently. Some count whole days, some count each class period, and some remove excused absences from the count. The tool does not know your rule, so enter the numbers the way your own rule counts them. If excused absences do not count against you, leave them out of the days held and the days missed.
The percent you need is also your own number. A school handbook or program agreement usually states it. The tool only turns it into days.
Planning the rest of the term
Knowing the number of days you can still miss helps you plan around illness, travel or appointments. If the limit has already been passed, the tool shows the highest rate you could reach by attending every remaining day, which tells you whether the target is still possible.
For related school math, use the percentage calculator, the grade calculator and the GPA calculator. The percent change calculator handles before and after values.
Assumptions and limits
- Days are whole numbers, and days attended cannot be more than days held.
- The term length is the total number of days or classes your rule counts, and it cannot be less than the days held so far.
- The tool is arithmetic and does not decide any policy or whether an absence is excused.
- The days you can still miss assume that every day counts the same.
Frequently asked questions
How do I calculate attendance percentage?
Divide the days attended by the days held and multiply by 100. For 82 days out of 90 that is 91.11%.
How many days can I miss and still keep 90% attendance?
Enter the term length and 90%. The tool finds how many days you must attend, rounded up, and subtracts from the term to give the most you can miss, then subtracts what you already missed.
Why does the tool round up the days I must attend?
Because a part of a day cannot count as attended. Rounding up makes sure the final rate really reaches the percent you need.
Does it handle excused absences?
Only if you enter the numbers that way. Leave excused days out of the days held and missed if your rule ignores them.