breaks on 1996 Nissan Sentra

my breaks have went out the peddle gose all the way to the floor what could this be

Asked by for the 1996 Nissan Sentra
If the brake pedal is going to the floor, then there are 2 possibilities. You have a leak in the brake system and the brake fluid has leaked out, or the master cylinder has failed (most common). Check the brake fluid level, if it is OK, then the master cylinder will need to be replaced. Have the brake fluid flushed at the same time too.