Proper cubic footage?
 

Boxes are tuned to a certain frequency at a certain size box and port. So, do you account for the amount of area the subs accumulate? My subs are about 1&1/2 cf so when they're in reversed the bass is much bigger. Do the makers of the "box calculators" take this into account? or am i suppose to? I ask because some subs take up very little space compared to an RE XXX.

Box volume recommended by a manufacturer is usually net volume, not including driver displacement, port displacement or any internal braces. You must make add these before calculating box dimensions if you install the sub normally. If you install it reversed, the volume of the box must be reduced by the driver displacement before you calculate the dimensions.
However, if a manufacturer provides dimensions, it usually inclues all of the above. If you now mount the woofre reversed you have to subtract 2x driver displacement and recalculate the dimensions.
If you take a look at your manufacturers web site this is usually mentioned.

As for driver displacement, check the specs. For example, JL 12W6 sub has 2.5 liters displacement and net internal volume for a sealed box is suggested at 42.5 liters. So the displacement is only 5.5% of the box volume. If you don't take that into account it may change the resonant frequency also by a few percent. Given many other variables in box design and performance, this may not make a huge difference.

Thank you, The RD Audio site just came back online but the box calculator is still under construction.