how many ounces are in a mcdonald's large cup
How McDonald's cup sizes vary across the globe - with the biggest in the U.S. at 30oz. 1  The U.S., Singapore and Canada go by the same definitions of 'small', 'medium' and 'large' - 16oz, 21oz and 30oz. 2  The smallest large-sized cup is in Japan, which is 20oz - the same as an American medium drink.