Is 4 oz enough?

Cheyenne
Hey everyone! I started pumping and bottle feeding my 2 week old and sticking to breastfeeding at night. When I pump I get about 4 oz total in 15 min. Is 4 oz plenty for a newborn during a feeding? I wanna make sure he's getting enough. Really don't wanna use formula. I pump every 2-3 hours all day except at night