Gigacalories to megacalories converter above calculates how many megacalories are in 'X' gigacalories (where 'X' is the number of gigacalories to convert to megacalories). In order to convert a value from gigacalories to megacalories (from Gcal to Mcal) simply type the number of Gcal to be converted to Mcal and then click on the 'convert' button.