A cove base cutting guide provides a stable guide for holding a cove of soft material, such as rubber or synthetic rubber, achieved in a bottom, top, ends and front and back sides with a cove-shaped chamber within, the integrity of the guide breached only by fully-contained slits on the front side within the front side and by a narrow opening the size and shape of a cove base in the ends for receiving and discharging a cove end piece cut from cove stock in the guide. To maintain the knife in alignment within the slit, the guide includes a chamber groove opposite each slit into which the end of the knife passes. The front slitted side is thin such that a conventional utility knife of length typically only about 1-inch reaches from the front side through the chamber into the guide grooves. In an alternative embodiment, a stabilizing block is attached to the guide back side to maintain guide structural stability when the chamber grooves are extended as slits through the guide back side and stabilizing block.