In the anime, Ash's pikachu has no known level, but it is at least 37 (Agility). In HeartGold and SoulSilver, Red has a level 88 Pikachu. In an event, Ash's pikachu is given out, and it says "had a fateful encounter at level 50". Still, the current level of Ash's Pikachu is Unknown. I hope this helps! -Jellohamster