What is the cubic feet of my washing machine?
Stick a measuring device inside.  Measure the depth and diameter.  Convert those to feet.  volume = height times (diameter / 2) ^ 2 * pi.

For example, my washer is 12 inches deep (a front loader) and 22 inches in diameter.  1 foot times (22/12 / 2)^2 * pi = 2.6 cubic feet.

To clarify:

12 inches = 1.0 feet

22 inches = 22/12 feet = 1.8333 feet

convert 1.83333 feet from diameter to radius by dividing by 2 = 0.916666 feet

1.0 x (0.91666) ^ 2  x &pi; =

0.84027777  x  &pi; =

0.84027777  x 3.141592 =

2.63980994