My Galaxy Note 4 is dropping to 1% battery out of nowhere.

I've had my Note 4 for almost 3 years now, it's still in great condition but the battery is starting to die. It drops pretty quickly on it's own but sometimes when I'm using it it will just go to 1%. The other day I just unplugged it from charing and it went straight from 99% to 1% after opening Waze for a couple seconds. Anyone know what could be happening? Is there a fix?