Calories (15 °C) to gigacalories converter on this page calculates how many gigacalories are in 'X' calories (15 °C) (where 'X' is the number of calories (15 °C) to convert to gigacalories). In order to convert a value from calories (15 °C) to gigacalories (from cal to Gcal) simply type the number of cal to be converted to Gcal and then click on the 'convert' button.