Here is a neat little room mode calculator that you can keep on your desktop, it's free to download and takes the math work out of the picture. Easy to read and use also.
Just click the (ModeCalc) link at the top of the page after you follow this link: http://realtraps.com/
Dave
Just click the (ModeCalc) link at the top of the page after you follow this link: http://realtraps.com/
Dave