In magnetics, the maximum energy product is an important figure-of-merit for the strength of a permanent magnet material. It is often denoted  and is typically given in units of either  (kilojoules per cubic meter, in SI electromagnetism) or  (mega-gauss-oersted, in gaussian electromagnetism). 1 MGOe is equivalent to .
During the 20th century, the maximum energy product of commercially available magnetic materials rose from around 1 MGOe (e.g. in KS Steel) to over 50 MGOe (in neodymium magnets). Other important permanent magnet properties include the remanence () and coercivity (); these quantities are also determined from the saturation loop and are related to the maximum energy product, though not directly.