Magnemite will evolve into Magneton starting at level 30, although it can be delayed by the player until any level after that. Magneton can then be further evolved into Magnezone in Pokemon games in the fourth generation and onward.
Magnemite can be evolved into Magneton by either leveling it up naturally by gaining experience points in battle, or by increasing its level synthetically with rare candies at a rate of one level per candy. To further evolve it again into Magnezone, players need to evolve Magneton one level in either Mt. Coronet, Kalos Route 13, New Mauville or Chargestone Cave to activate the evolution sequence.