A tool for calibrating a non-contact tonometer (NCT) comprises a body having a mating feature configured for removably mounting the body on the nosepiece or on the measurement head of the NCT, a pressure sensor carried by the body and arranged to receive an air pulse discharged by the NCT to provide a pressure signal in response to the air pulse, and a radiation emitter carried by the body, wherein the radiation emitter provides a pseudo-applanation event when the pressure signal reaches a predetermined level that is detectable by the NCT as though an actual corneal applanation had taken place. In one embodiment, the mating feature includes a mounting orifice for receiving a portion of the nosepiece. In another embodiment, the mating feature includes a pair of mounting pins sized for receipt by a corresponding pair of mounting holes in the measurement head of the NCT.