Abstract: A method and apparatus for calculating a torque constant, Kt, of an actuator for a computer disk drive by passing the actuator through a magnetic field and measuring the induced change in potential. A stepper motor moves the coil through a magnetic field (either by rotation or linear movement), and a fluxmeter measures changes in flux. The measurements are synchronized using an encoder which commands a digital multimeter to sample the fluxmeter. By passing the actuator in both a forward and a reverse direction, the contribution based on voltage integrator drift is reduced. This method and system are not influenced by the torque from mechanical effects such as friction or torque from the current carrying leads.