Milliwatts to ergs per hour conversion calculator shown above calculates how many ergs per hour are in 'X' milliwatts (where 'X' is the number of milliwatts to convert to ergs per hour). In order to convert a value from milliwatts to ergs per hour (from mW to erg/h) type the number of mW to be converted to erg/h and then click on the 'convert' button.