What is how old are phineas and ferb?

Phineas and Ferb are fictional characters from the animated television series “Phineas and Ferb”. The show premiered on August 17, 2007, and ran for four seasons. Phineas Flynn is a 9-year-old boy, while Ferb Fletcher is his stepbrother who is the same age. Throughout the series, they engage in imaginative and creative adventures, often building incredible inventions that defy reality.