Combo expressed and formula, how much?

[SuddenArborealStop]

I'm going to stop breastfeeding and start combo feeding expressed and formula until my milk dries up.
Can I use the recommended oz per day chart on he formula to apply to both types of milk together or is there another trick to it.
I've seen calculators for ebf and formula but not sure about expressed and formula.

In all honesty, I don’t know how much they should be having if they are combo fed but I wouldn’t use the guide on the formula carton as baby will not drink nearly enough at first for two main reasons:

BF babies generally take 25 floz in 24 hours between 6 weeks and 6 months. FF babies need 2.5floz per pound in weight in 24 hours. So a 15lb baby will need roughly 37.5 floz of formula.

Another thing is that a BF baby is unlikely to take much formula at first. They are used to drinking around one floz per hour, so if your baby hasn’t fed for 3 hours, they’ll take around 3 floz. This won’t apply to all babies obviously but it may take a while before they are taking any kind of quantity in the bottle.

All of this changes of course once they’re 6 months when they only need roughly 20floz of formula a day.

Having said all of that, I’d give one of the BFing Helplines a call as the BFC should actually be able to answer your question