The cubic feet of a refrigerator model aren't always listed on its model label, but once you find the model number on the label, you can track down the model's specification sheet on the manufacturer's website.
Running the Numbers
If you need to determine the cubic feet of a discontinued model for which official information is lacking, remove the shelves, drawers and trays -- if necessary -- from the refrigerator and freezer. You may be able to readily poke your measuring tape around obstructions without removing these items.
Measure the height, width and depth in inches and multiply these figures. Divide the total by 1,728 to arrive at the interior capacity of the refrigerator in cubic feet.
For example, if you have -- for the sake of a simple example -- a refrigerator-only whose interior compartment measures 53 inches tall, 27 inches wide and 24 inches deep, you perform this calculation:
53 x 27 x 24 = 3,434
3,434/1,728 = 19.8 cubic feet
Losing Inches Here and There
Real Simple points out that for a refrigerator/freezer, the cubic feet figure can be misleading, as it implies unrestricted refrigeration area. For example, an 18-cubic-foot model may devote 5 cubic feet to the freezer, and its 12 cubic feet of fridge space may be chopped up by bins and shelves. Consumer Reports' engineers, for example, subtract volume for such things as obstructions on top shelves and hardware.
Upscale newer models, though, allow extensive customization of the interior space. And with 18 to 24 cubic feet recommended for a family of four, you can get more useable space for each cubic foot with better designed refrigerators.