adding part of a function on condition.

My spreadsheet image is below...

http://www.digitaluprising.net/site/...l_untitled.JPG

What i'm trying to do is, at present, all my lengths are in feet... but sometimes i need inches... so what i want to do is...make the board foot function add an additional "/12" to my current funtion "=H20*F20*D20/12" when i fill in a lenght as 120" vs 120. Even if i could use a checkbox to add the additional "/12" to my function that would be helpful!
Thanks!

anyone have any thoughts at all that *might* get the desired results?

perhaps even something like if checkbox= clicked cell:b17 = "formula1" and if checkbox= unclicked cell:b17 = "formula2"

??

Lets say you have a checkbox from the forms menu and link it to cell A1. Now when you check the box, cell A1 will have true, and when you uncheck, it will have false.

Now to all your formulae which use the length which is entered in inches or feet, you can add this part.

then
=H20*F20*D20/(if(A1,12,1))

If you check the box, A1 will be true, and your formula will be divided by 12, and if the box is unchecked, then A1 is false, and your formula will be divided by 1.

Mangesh

absolutly perfect!
Thanks!