Centimeters of mercury to hectopascals conversion calculator above calculates how many hectopascals are in 'X' centimeters of mercury (where 'X' is the number of centimeters of mercury to convert to hectopascals). In order to convert a value from centimeters of mercury to hectopascals (from cmHg to hPa) just type the number of cmHg to be converted to hPa and then click on the 'convert' button.