According to Barcelona's official website, Barca may owe Valencia another €3m in variables.
The Spaniard has signed a five-year deal with the Catalan club and his contract includes a buy-out clause of €100m.
Luis Enrique's side have been searching all summer for a fourth striker to accompany Lionel Messi, Luis Suarez and Neymar at the Camp Nou.
The 22-year-old will be presented to the Barcelona fans when he returns from the international break with Spain.
The move will also see Barcelona's young striker Munir join Valencia on loan.