What are the dimensions of a bale of hay?

A square bale of hay is usually 2 feet wide, 4 feet long, and 2 feet tall. A round bale of hay varies, depending on the baling equipment. The dimensions usually range from 4 ft x 4 ft to 4 ft x 6 ft.

Edit: There are three sizes of square bales, small medium and large. Small bales are 2'x2'x4'. The advantage of these bales is they can be carried by hand for use in 1-2 horse/cow feeding situations. I am not positive of the larger two dimensions, but medium bales are around 4'x4'x6', and large bales around 6'-8' square by 8'-10' long. Weight depends on the type of hay and settings of the baling equipment. Round bales also vary in sizes, the smallest of which is around 4' tall.

Edit2: Manufacturers use the term "Square" bales to differentiate between those and round bales, even though the bales are rectangular. The small and medium size balers have a fixed bale chamber that produces a bale that is either 14"x18" or 16"x18". The length can be varied to produce bales between 36" and 41". This is the range of length that is required by most automatic bale wagons that are used to pick-up the bales in the field and stack them. Occasionally you will find a bale that is 46" long, but most bales that you would purchase at the feed store are 41" long. If you are buying hay and paying by the bale, you will usually see the smaller 14"x18" bale but will see the larger 16"x18" bales when buying by the ton.

Given the mentioned range, most bales produced for hand loading are 16"x18"x41"