At a particular time certain sellers are offering their homes and certain buyers are interested in purchasing homes similar to them.
The tax appraiser and the mortgage appraiser may tell you a single number (usually different ones), but the reality is that the buyer and the seller who come to agreement are the market at that moment. At a different point in time with different buyers and sellers "the market" will come up with a different answer.
Even the mortgage appraiser using USPAP rules has significant latitude in stating a value. You can investigate these rules, but the bottom line is that the bottom line can be different by plus or minus 15% and still be within the rules. That's a lot of difference. So, the home you're looking at should sell with a high probability within that 15% up or down range, depending on the market at the moment.
Fair is a term that exists only in the minds of buyer and seller. Of course the seller wants as much as he can get and the wants to pay as little as possible. Each will tell you it's fair to the other. But what they agree on is the actual fair value.
Your Realtor can supply you a comparison of similar houses that sold recently to help you see what others have agred on. You can try the link I've included below to see a fairly automated survey of currently available prices and recently sold houses.
Good luck to you!
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I would suggest contacting a few experienced agents close to the home and ask them to provide you with comps of recently sold homes. Ask them to provide you with every single sold home close to the property in the last six months. Then, I would suggest you drive by every single home that recently sold near the home of interest to you and review the area and home. After reviewing the pictures and information online and driving by each one, you should have a real good idea of the fair market value of the property of interest to you. Best wishes.
The absolute best way to determine a property's fair market value is to have it professionally appraised. It sounds like you are trying to identify similar comparison properties.....this can be confusing. Put it in the hands of a professional and have an appraisal done.
that's how Appraiser's give value and how we come up with a listing price for a property. Not appraisal district values. If you are working with a Realtor they can do that for you, if you don't have a Realtor then you can email me I'll do that for you.