Kalophrynus calciphilus was described from Gunung Mulu National Park in eastern Sarawak (Dehling 2011). It is endemic to the karst forest within the park, where it occurs at elevations between 70 and at least 1200 m above sea level. It is one of the most abundant species in this forest type. Males can be found calling from the entrances of burrows and crevices in the ground. The call is a single, short note composed of 7–9 pulses.

The reproductive mode and tadpoles of this species are unknown. It is a medium-sized member of the genus, with males reaching up to 30 mm in snout–vent length (SVL) and females up to 39 mm.

At night, the back and flanks are black. During the day, the coloration lightens to brown, revealing a fine pattern of reticulated black markings. A white line runs along each side of the body from the tip of the snout to the groin. Like other species in the genus, K. calciphilus secretes a sticky mucus when threatened.