Abstract: A screw thread measuring device capable of measuring the physical parameters of internally or externally threaded parts comprising a base and slidable platform. Measuring segments are mounted to the base and platform, respectively. Gage mounts to the base and contacts the platform with plunger. To measure an externally threaded part, the externally threaded part is placed between base mounted measuring segments and platform mounted segment. The measuring segments are biased together. Plunger of the gage correspondingly moves with the platform to measure the displacement of the platform with respect to the base. The distance the platform moves is read out on the dial of gage. To measure an internally threaded part, the measuring segments are replaced with measuring segments designed for internally threaded parts. The threaded parts are inserted into the internally threaded part and the platform is biased away from base mounted segment.