how do you know what speed record
Turntables: Record Sizes. Vinyl records come in three varieties, measured in revolutions per minute (rpm): the 33 1/3 rpm, the 78 rpm, and the 45 rpm. Each variety is a different size and revolves at different speeds. The most common records today are the 33 1/3 rpm and the 45 rpm. A 78 rpm record is 10 inches in diameter.