To figure how much you may deduct for property that you contribute, you must first determine its fair market value on the date of the contribution.
Fair market value.
Fair market value (FMV) is the price that property would sell for on the open market. It is the price that would be agreed on between a willing buyer and a willing seller, with neither being required to act, and both having reasonable knowledge of the relevant facts. If you put a restriction on the use of property you donate, the FMV must reflect that restriction.
Determining the value of donated property would be a simple matter if you could rely only on fixed formulas, rules, or methods. Usually it is not that simple. Using such formulas, etc., seldom results in an acceptable determination of FMV. There is no single formula that always applies when determining the value of property.