The conductance indicates how easily current can flow through a resistor. It is the reciprocal of the resistance. The measurement unit is siemens (previously called mho), which is equal to 1 ampere/volt, or 1 ohm-1.
To calculate the conductance (G), you divide the current (I) through the resistor by the voltage (V) across it, G = I / V, or you take the reciprocal of the resistance, G = 1 / R.