How to calculate the number of the cells and their RANGE for Predfined AREA in EXCEL (BY WIDTH AND HEIGHT IN PIXELS)

[archanasinghvi]

Hi,
i will explain you the things one more clear way.
lets have the snapshot.

so as per the image , the user will select the GRID SIZE, then template and according to this it will select the WIDTH and HEIGHT in PIXELS.
so the CELL WIDTH AND HEIGHT WILL BE ADJUSTED EQUAL TO GRID SIZE IN PIXELS.
and then it will CALCULATE THE TOTAL NO OF CELLS FOR THE SELECTED WIDTH AND HEIGHT IN PIXELS.
SO THAT IT CAN PAINT THOESE CELLS ONLY IN WHITE COLOR FOR STARTING DESIGNING.
LETS SUPPOSE IT WILL SELECT THE CELLS STRATING FROM A1 to equal to that width and height in pixels.
YOU CAN UNDERSTAND IT AS in non technical term YOU have a big RECTANGLE and you have to draw a small rectangle in it for particular width and height.
please see how it will happen

Are you able to see the above screen , the result will come in this form. The particular cells are counted on the BASIS OF grid SIZE, WIDTH AND HEIGHT in pixels are painted WHITE . REST CELLS ARE SAME.
MAY BE i am not that much technical expert in telling you the techy things but this is my requirement.
Please help me so that i can proceed ahaed.