graphics memory vs pixelformat

How can I calculate the memory usage from the PIXELFORMATDESCRIPTOR. I am using WOGL functions.

I seems my program works even the memory usage
over the limit of my graphics card.
I calculated the memory based on the pixel format
such as color bit and depth bit.

For example,
MB=
(1600*1200 resolution) *(32 bit color+ 24 depth+ etc)/1024/1024

Is there something else I missed?

-KB

You mixed bits and bytes.
use :
(1600*1200 resolution) (32 bit color+ 24 depth+ etc)/8/1024/1024
or :
(1600
1200 resolution) *(4 bytes color+ 3 bytes depth+ etc)/1024/1024