Instrument for determination of dimensional characteristics (sides, straightness of edges, orthogonality, curvature the sides, center and warpage) of tiles, plates and/or plain plates and similar products. Static positioning with respect to the points required by the standards is innovative, and particularly the measurement of the curvature of the sides, the centerand the warping is carried out using magnetic blocks carrying laser sensors that are simple but precise to use. Measurement of the points required by the standards is carried out using laser sensors (laser rangefinders).