Calculating Flip Finance Costs

[Ross Bernard]

I am interested in taking on my first flip project. So, let's assume I'm perfect at estimating rehab costs and at coming up with the ARV. Now, how do I accurately calculate financing costs before making an offer to the bank? I believe I want to use a portfolio lender, and will be using a general contractor. Will a portfolio lender be able to give me all the specific costs involved before a house is under contract? Would they say, hypothetically, "You are approved for this much money at this rate with this many points and these other fees, now bring us a good deal." Or will they only give specifics on a specific deal? I feel like I understand how conventional financing works pretty well, but not portfolio lending. I'm looking to buy properties with an ARV of approx $100k.

Other info that might help: My FICO is excellent, $30k total to put in the deal, $50k in retirement, $60k in equity between primary residence and one rental