Hectopascals to inches of water converter above calculates how many inches of water are in 'X' hectopascals (where 'X' is the number of hectopascals to convert to inches of water). In order to convert a value from hectopascals to inches of water (from hPa to inH2O) simply type the number of hPa to be converted to inH2O and then click on the 'convert' button.