The Heuer Calculator is one of the most unapologetically functional chronographs of the 1970s, created at a time when the company was producing increasingly specialised instruments for drivers, pilots and professionals. Introduced in 1972, its defining feature is the enormous circular slide rule surrounding the dial. By rotating the outer scale against the fixed inner scale, the wearer could perform multiplication and division as well as calculations and conversions involving speed, distance, fuel consumption, weight and volume – effectively placing a mechanical calculator on the wrist years before electronic devices made such tools redundant.

Reference 110.633 combines that functionality with the bold design language that defined Heuer during the period. Its substantial 45mm stainless steel tonneau case surrounds a blue dial punctuated by vivid orange chronograph hands, while the crown positioned on the left side of the case immediately identifies the automatic Chronomatic architecture within. Power comes from Heuer's calibre 12, pairing a micro-rotor automatic base movement with a Dubois-Dépraz chronograph module. Large, technically ambitious and unmistakably of its era, the Calculator represents Heuer at perhaps its most tool-focused: a watch designed not simply to measure elapsed time, but to perform calculations directly from the wrist.