is one of the three classic approaches to estimating the value of real property. In the cost approach, the site and the improvements are valued separately. The focus in applying the cost approach is on the current value or current cost of the improvements. The improvements are valued at the current cost new minus any loss in value due to depreciation. The depreciated cost of the improvements is then added to the site value to provide an indication of the value of the property.

It is considered most reliable when appraising properties with new improvements or when appraising properties that have unusual improvements for which there are no market comparables.