How to determine repair/reno costs before making an offer?

[Laura Levine]

Hi guys,

How do you determine how much a reno is going to cost? I don't have enough experience yet to estimate costs myself and I'm new to the area and don't have an established relationship with any contractors. I've found myself in kind of a catch-22 because contractors don't want to come and give me a general estimate until I'm at least under contract, but whether I make an offer is contingent on ensuring that the reno costs will make it a viable purchase? Any suggestions would be really appreciated, thanks!