It really depends on what formula you’re using as each will have different calories especially if it’s not standard formula like kendamil
My boy is 12 weeks too and having 5oz every 3 hours except for his bottle before bed which is 6oz
Mines 13 weeks and has 5oz every 3 hours ,x
My little boy is having 6oz every 4/5 hour. He is 10 weeks old. He ends up having about 5 bottles in a 24 hour period x