Real estate appraisal is the practice of developing an opinion of the value of real property, usually its Market Value. (Real estate appraisal is American usage; many other countries use the terms property valuation or land valuation.) The need for appraisals arises from the heterogenous nature of property as an investment class: no two properties are identical, and all properties differ from each other in their location - which is the most important determinant of their value. So there cannot exist a centralised Walrasian auction setting for the trading of property assets, as there exists for trade in corporate stock. The absence of a market-based pricing mechanism determines the need for an expert appraisal/valuation of real estate/property.

A real estate appraisal is performed by a licensed or certified appraiser (in many countries known as a property valuer or land valuer). If the appraiser's opinion is based on Market Value, then it must also be based on the Highest and Best Use of the real property. For mortgage valuations of improved residential property in the US, the appraisal is most often reported on a standardized form, such as the Uniform Residential Appraisal Report. Appraisals of more complex property (e.g. -- income producing, raw land) are usually reported in a narrative appraisal report.