An apparatus for calculating torque of a variable capacity compressor, including: a sensor configured to detect internal and external states of an air conditioner; an OFF-torque calculator configured to calculate and store a steady-state torque according to a state detected by the sensor just before a clutch is turned off; a start torque calculator configured to calculate a start torque according to a state detected by the sensor after the clutch is turned on; a steady-state full-stroke calculator configured to calculate a steady-state full-stroke torque based on an assumption that the compressor was in a full-stroke-state according to a state detected by the sensor after the clutch is turned on; and a determiner configured to provide, when an elapsed time after the clutch is turned on is less than a predetermined time, a maximum one of the torque values calculated by the OFF-torque calculator, start torque calculator, and steady-state full-stroke calculator.