Centimeters of water to inches of water conversion calculator shown above calculates how many inches of water are in 'X' centimeters of water (where 'X' is the number of centimeters of water to convert to inches of water). In order to convert a value from centimeters of water to inches of water (from cmH2O to inH2O) type the number of cmH2O to be converted to inH2O and then click on the 'convert' button.