Calw is located in the valley of the Nagold in the Northern Black Forest at an altitude between 330 and 630 metres above sea level.
Calw has 13 subdivisions known as Stadtteile (quarters or neighborhoods): Altburg, Oberriedt, Speßhardt, Spindlershof, Weltenschwann, Calw, Alzenberg, Heumaden, Wimberg, Hirsau, Ernstmühl, Holzbronn und Stammheim.