When to evolve Pikachu in FireRed and LeafGreen
Choose a Thunder Stone timing based on Pikachu’s level-up moves instead of following one unexplained level recommendation.
Scope: Generation III FireRed and LeafGreen learnsets
Quick answer
Pikachu can evolve as soon as you obtain a Thunder Stone, but Raichu learns almost no new moves by leveling in FireRed and LeafGreen. A practical choice is to wait until Pikachu learns Thunderbolt at level 26, then evolve; evolve earlier only if you plan to supply the moves you need with TMs or tutors.
Practical recommendation
For a normal playthrough, level 26 is a useful evolution point because Pikachu learns Thunderbolt at that level in FireRed and LeafGreen. Use a Thunder Stone after the move is learned if you want Raichu without relying on the Thunderbolt TM.
This is a recommendation, not a hidden requirement. You can evolve earlier when your planned moves come from TMs, tutors or breeding, or wait longer for Pikachu’s later level-up moves.
Moves Pikachu learns first
In these Generation III games, Pikachu learns Thunderbolt at level 26, Agility at 33, Thunder at 41 and Light Screen at 50. Raichu does not continue that same level-up sequence, so using the stone immediately can close off the convenient route to those moves. TMs may provide another route, but each TM has its own availability.
Getting a Thunder Stone
The Celadon Department Store sells Thunder Stones on the fourth floor, making the evolution choice available after reaching Celadon City. Save before evolving if you are still deciding on the moveset; evolution itself cannot be reversed.
Sources
Official Pokémon and Nintendo pages anchor current facts. Community references are used to locate version-specific questions, then cross-checked before publication.