Calories per day to ergs per second conversion calculator above calculates how many ergs per second are in 'X' calories per day (where 'X' is the number of calories per day to convert to ergs per second). In order to convert a value from calories per day to ergs per second (from cal/d to erg/s) simply type the number of cal/d to be converted to erg/s and then click on the 'convert' button.