Mayor Bill de Blasio and Schools Chancellor Meisha Porter announced Wednesday morning that 3-K would be expanded to all New York City school districts this September and will be free.

Porter says this is a big deal and couldn't come at a better time as parents begin to return to the office. Porter says 3-K is free and will save parents about $10,000 a year.

De Blasio says being able to offer free 3-K, which is pre-K for 3-year-olds, was made possible through funding from the stimulus bill.

MORE: Live Blog

Offering 3-K adds more than 16,000 students to city schools.

The program gives students a chance to get a head-start on schooling, which officials say helps close achievement and opportunity gaps for children.

"3-K is the absolute guarantor of a brighter academic future for a child but also for a parent," says de Blasio. "It takes so much stress out of their life to know that their kid is in a safe place, they're getting a good education. It's free. This is a game-changer for parents."

De Blasio says the program expansion will start as early as this September.