How much do they need

How much sleep at night does baby need. My 3 month old gets roughly 7-8 hours sleep at night. She wakes up for feeding but only drinks 2oz when normally through the day she drinks 4-5oz. I’m trying get her to sleep though the night so she can get more sleep. When she does wake up at night it’s usually only long enough to eat and be changed and she is back to sleep so 15 min. How much sleep is you ladies baby getting a night??????I have the owlet so it tracks her sleep.