The FHA Refinance Loan Maximum Mortgage Calculation – For non-streamline, appraisal-required FHA refinance loans that feature no cash back to the borrower, FHA loans rules state that the maximum mortgage for a no cash out refinance with an appraisal (credit qualifying) "is the lesser of the 97.75% Loan-To-Value (ltv) factor applied to the appraised value of the property or existing debt."