An electrosurgical system comprising: an electrosurgical generator comprising: a power supply configured to output a DC waveform; a power converter coupled to the power supply and configured to generate a radio frequency waveform based on the DC waveform; an active terminal coupled to the power converter and configured to couple to a first electrosurgical instrument and a second electrosurgical instrument (20"); at least one sensor coupled to the power converter and configured to sense at least one property of the radio frequency waveform; and a controller coupled to the power converter, the controller configured to: determine a first impedance associated with a first electrosurgical instrument and a second impedance associated with a second electrosurgical instrument based on the at least one property of the radio frequency waveform; and adjust at least one parameter of the radio frequency waveform based on the first impedance and the second impedance; the system further comprising the first electrosurgical instrument and the second electrosurgical instrument (20") both operably coupled to the electrosurgical generator via the active terminal; wherein the first electrosurgical instrument is, in use, activated prior to the second electrosurgical instrument, wherein the system is characterized in that the at least one sensor is configured to measure first voltage and current of the radiofrequency waveform supplied to the first electrosurgical instrument, the controller configured to determine the first impedance prior to activation of the second electrosurgical instrument based on the measured first voltage and current, and in that the at least one sensor is configured to measure total voltage and current of the radiofrequency waveform supplied to the first and second electrosurgical instruments, the controller configured to determine total impedance after activation of the first electrosurgical instrument and the second electrosurgical instrument, and in that the controller is configured to determine the second impedance based on the total impedance and the first impedance. an electrosurgical generator comprising: a power supply configured to output a DC waveform; a power converter coupled to the power supply and configured to generate a radio frequency waveform based on the DC waveform; an active terminal coupled to the power converter and configured to couple to a first electrosurgical instrument and a second electrosurgical instrument (20"); at least one sensor coupled to the power converter and configured to sense at least one property of the radio frequency waveform; and a controller coupled to the power converter, the controller configured to: determine a first impedance associated with a first electrosurgical instrument and a second impedance associated with a second electrosurgical instrument based on the at least one property of the radio frequency waveform; and adjust at least one parameter of the radio frequency waveform based on the first impedance and the second impedance; a power supply configured to output a DC waveform; a power converter coupled to the power supply and configured to generate a radio frequency waveform based on the DC waveform; an active terminal coupled to the power converter and configured to couple to a first electrosurgical instrument and a second electrosurgical instrument (20"); at least one sensor coupled to the power converter and configured to sense at least one property of the radio frequency waveform; and a controller coupled to the power converter, the controller configured to: determine a first impedance associated with a first electrosurgical instrument and a second impedance associated with a second electrosurgical instrument based on the at least one property of the radio frequency waveform; and adjust at least one parameter of the radio frequency waveform based on the first impedance and the second impedance; determine a first impedance associated with a first electrosurgical instrument and a second impedance associated with a second electrosurgical instrument based on the at least one property of the radio frequency waveform; and adjust at least one parameter of the radio frequency waveform based on the first impedance and the second impedance; the system further comprising the first electrosurgical instrument and the second electrosurgical instrument (20") both operably coupled to the electrosurgical generator via the active terminal; wherein the first electrosurgical instrument is, in use, activated prior to the second electrosurgical instrument, wherein the system is characterized in that the at least one sensor is configured to measure first voltage and current of the radiofrequency waveform supplied to the first electrosurgical instrument, the controller configured to determine the first impedance prior to activation of the second electrosurgical instrument based on the measured first voltage and current, and in that the at least one sensor is configured to measure total voltage and current of the radiofrequency waveform supplied to the first and second electrosurgical instruments, the controller configured to determine total impedance after activation of the first electrosurgical instrument and the second electrosurgical instrument, and in that the controller is configured to determine the second impedance based on the total impedance and the first impedance.