I started giving my daughter formula this week from EBF (she's still nursing in the mornings). I'm curious to see how much your babies are eating. Her ped said to start with 5 ounces every 3 hours (4 of breast and 1 of formula) and each day increase the formula by 1 oz and decrease breast by 1 oz. By yesterday she was having all formula bottles. But today she still seemed hungry and was crying for more so I gave her 6 oz bottles. She's 15lbs and 28.5 inches. She turned 4 months on the 23rd.