An inexpensive appraisal instrument is provided for measuring unknown dimensions of a house or building from a remote observation point such as from a car in a street near the building. The instrument is sighted and calibrated on a door, which is of a standard height, and thereby identifies by comparison the unknown dimensions such as width, height, driveway, windowframes, garage, etc., so that an appraisal report can be made without entry on the property. The instrument comprises a telescopically acting rod spacing a cross member variably from a datum-apex point so that the door may be sighted through a pair of spaced sights for calibration. There is a measurement scale in feet or meters gaged from the door dimensions on the cross member so that a second sighting from the same observation point of a member of unknown dimension establishes an angle identifying a span from which the unknown member measurement may be directly read on the measurement scale.