This calculator allows you to convert from Foot water (4°C) to Millimeter mercury (0°C) and in a reverse direction. To convert from Foot water (4°C) to Millimeter mercury (0°C), enter the amount of Foot water (4°C) into the first input and to convert from Millimeter mercury (0°C) to Foot water (4°C), enter the amount of Millimeter mercury (0°C) into the second input.