Tyrogue evolves into Hitmontop at level 20 if its attack and defensive stats are equal. If the attack stat is higher than the defense, Tyrogue evolves into a Hitmonlee. If the defense stat is higher, Tyrogue evolves into a Hitmonchan.
Tyrogue is a baby Pokémon that first appeared in Generation II. In Pokémon Gold and Silver versions, players would receive one Tyrogue from Kiyo in Mt. Mortar. After the Tyrogue evolves, players can breed the evolved Pokémon to produce more. All Tyrogues are male, so players need to breed it with a Ditto to produce an egg. This gives players more chances to evolve Tyrogue into a Hitmontop.
Players can attempt to calculate and control stats as Tyrogue levels up. Online calculators can help players figure out stats based on nature and level. Players can then decide to give Tyrogue stat boosting items. Special one-time use items can also raise attack and defense stats. If these are used, they should be used when Tyrogue is at a high level.
If Tyrogue is about to gain enough experience to become level 20, but the stats are not what the player wants, the player can press the B button to stop the process.