A power calibration algorithm is performed on a wireless communication device, where power measurements are taken across frequency sweep at the output of the device and at a power amplifier of the device, to accurately track voltage standing wave ratio impedance and errors associated with VSWR impedance. The measurements are performed as part of production of the wireless communication device and during online operation of the wireless communication device. During online operation the measurements are made by a detector at the power amplifier over the various frequencies of the frequency sweep.