Brittle and ductile fracture surfaces of low-carbon steel specimens having different grain sizes were investigated by means of confocal laser scanning microscopy in conjunction with conventional scanning electron microscopy and electron backscattered diffraction. The fracture surfaces were quantitatively characterized in terms of the areal surface roughness and normalized surface area. It was demonstrated that the normalized fracture surface area rather than areal roughness can be used as a measure of fracture surface ductility. The misorientation between cleavage facets and their diameters were evaluated statistically. Good agreement was found between characteristics of fracture surface elements and the underlying microstructure.