How big inside (cubic ft.) is the Roper refridgerator

20.9 cubic feet for model # RT21AKXKQ

14 cubic feet for model number RT14BKXKQ05

You can just take a few measurements,and find the volume yourself.To find how much volume there is in cubic feet multiply the height(h) by the width(w) by the length(l).so volume = h * w * l all measurements must be in feet so if one measurement for example is 1 foot,and 6 inches you would use 1 and 6/12 of a foot as the measurement or 1.5 feet.If the space isn't a perfect rectangular shape you have to break up the space into rectangular shapes and add the volumes together. Also you can do the volume of a larger rectangular cube,and subtract the volumes of the shelves for example from the total volume.so if the shelf is 1 inch high 2 feet long,and 2 feet wide.You would multiply 2 * 2 * 1/12 then subtract it from the total volume.which would be 1/3 of a cubic foot in volume (the shelf)