A method for calibrating a fly height adjustment device comprises flying a magnetic transducer coupled with a head gimbal assembly at a fly height from a magnetic recording data track. The magnetic transducer is coupled with a fly height adjustment device. Read-back signal amplitude is read from the magnetic recording data track with the magnetic transducer. The fly height is decreased with the fly height adjustment device. A linear fly height prediction is generated from the read-back signal amplitude and from power delivered to the fly height adjustment device as the fly height is decreased. The power delivered to the fly height adjustment device is compared with a difference between the linear fly height prediction and an implied fly height from the read-back signal amplitude, thereby calibrating the fly height adjustment device.