Excel formula to calculate percentage attendance

Question : Excel formula to calculate percentage attendance

 Hi guys,

I’m looking for help with an Excel formula – here’s what I need to do:

I am a teacher and want to track student attendance using an Excel sheet that calculates percentage attendance.

I designate one cell for each lesson in the year and want to mark an X in the cell if a student is absent.
At any one point in time I want to be able to look at the sheet and see what a student’s percentage attendance is THUS FAR. So they start out with a full 100% and this is reduced accordingly whenever an X is put in a cell – but it should be a formula that makes the percentage reflect their attendance in relation to the number of classes they’ve attended or not attended SO FAR.

So if, for instance, there are 184 classes in total in the year (this is just an example, there aren’t) – I might like to know their percentage attendance after class 5. And if they’ve attended 4 out of 5, I’d like that expressed as a percentage (rather than 4 out of 184) .

I’m not expressing myself too well. I hope u know what I mean – fi not, pls ask for clarification.

Thanks in advance for your time and effort,

Solution: Excel formula to calculate percentage attendance

I’m assuming this:
There are headers on first row of the sheet
Student’s names are in column A, starting in cell A2
Student’s absence is marked with “x” in columns B:Y (first studen’ts absence in range B2:Y2)
If a student is attending, the studen’ts cell for that class (in column B:Y) is empty.

Use this approach:
1. Type number of classes this far in cell Z1
2. Enter this formula in cell Z2:
=100% – COUNTIF(B2:Z2, “X”) / $Z$2
3. Copy the formula from Z2 as far down as necessary

If a studen’ts absence is marked in the range B2:Z2