Measure the distance around the outside of your washer. This is how large your plywood needs to be. When you purchase the wood, many times a hardware store will cut it to size for you for a small fee to save you the trouble. For an example, assume the washer is a perfect square of 25 inches on each side. The first piece of plywood serves as the top of the stand and is 25-by-25 inches.
Cut two pieces of plywood to function as the sides of your stand. They should have the same length as the side of the washer and be as high as you want the pedestal to stand. Typical pedestals from a store measure approximately 15 inches high. Cut two pieces of plywood into 25-by-15 inch pieces.
Cut six 2-by-4 pieces of lumber. The two for the length should be 23 inches long and the four for the legs should be 13 inches long. The reason for the shorter lengths is because you want the wood to fit together seamlessly, and the plywood is an inch thick on each side and needs to be subtracted from the overall length of the 2-by-4 pieces.
Place two of the 13-inch 2-by-4 pieces under one of the 25-inch 2-by-4 pieces to function as the legs. Use 3-inch screws if using a drill or nails if using a hammer.
Repeat for the other side of the pedestal.
Nail or screw the side panels onto each side of the stand. Do the same for the top. All wood pieces will be flush against each other.
Paint or stain the wood to match your room design or decor.