Abstract: A hand-held microcomputer-based ruler-like measuring and calculating instrument, particularly adapted for but not restricted to the graphic arts field, is capable of registering individual size measurements, proportioning successive readings in percent, converting to different units and visually displaying numeric results. The measuring, computing and indicating system has been human-engineered to eliminate fatigue and risk of error associated with conventional methods of repeatedly sizing and proportioning graphics elements. Distance along a fixed ruler scale, gaged by a slider-mounted pointer, is sensed and encoded electro-optically from an internal fixed bar-scale, digitally decoded, registered, processed and displayed. Optional audible indication enables the sliding pointer to be reset manually to a memory-stored reference point without eye contact, simplifying multiple sequential readings and proportioning factor determinations and thus greatly reducing mental and visual effort.