Fati, 17, has made nine appearances in La Liga this season, scoring two goals.
The Camp Nou side also stated the buy-out clause will automatically go up to €400m when he signs a professional contract as a full member of the first team.
“For me, La Masia [Barca’s academy] is the best school in the world,” Fati said. “They helped me from the first day I arrived and I am extremely grateful to everyone who works there.
“They are all spectacular. From the first day, I have learned things from everyone. And they have also been there to support me through difficult times.”
“Working every day with the best is a dream, and also a reward. From now onwards, what I have to do is keep working, even harder than ever, to keep getting chances and carry on on enjoying myself. The rest will come after.”
— FC Barcelona (@FCBarcelona) December 4, 2019
Fati made his debut at the age of 16 in Barcelona’s second La Liga game of the season in the 5-2 win over Real Betis and became the youngest player to start a league game at Camp Nou for the Catalans.
In his very next match — a 2-2 home draw against Osasuna — he became the youngest player to score and assist in the same match in La Liga history.