Centimeters of water to inches of mercury conversion calculator shown above calculates how many inches of mercury are in 'X' centimeters of water (where 'X' is the number of centimeters of water to convert to inches of mercury). In order to convert a value from centimeters of water to inches of mercury (from cmH2O to inHg) simply type the number of cmH2O to be converted to inHg and then click on the 'convert' button.