The stat system goes up to 5. However, by the end of Shippuden , both Naruto and Sasuke are so powerful that the scale breaks.
Canonical explanations of how specific techniques work, including their classification (e.g., Hiden, Kekkei Genkai) and elemental affinity. Shinobi Facts: Naruto Databook Pdf
Whether you are a powerscaler looking for the exact speed gap between Minato and Tobirama, or a cosplayer trying to figure out the correct symbol on a vest, the Naruto Databook PDF is an invaluable resource. Just remember to wield those stats with caution—and never tell a Jiraiya fan that his "5" in Ninjutsu equals Naruto's "5." You might start a war. The stat system goes up to 5