Wire size calculators use metric measurements, but not imperial measurements. However, a chart is available to convert metric measurements to imperial measurements once the measurement has been calculated.
The chart offers wire number, measurements in inches and measurements in metric units. The imperial measurements are given with the American Wire Gauge measurements. Wire size calculators use both inches and metric measurements. However, specific instructions are given to obtain the American Wire Gauge from both inches and metric measurements.
The Wire Gauge and Diameter Calculator offered online by 66pacific is one calculator that offers the option to use either English measurements or metric measurements.