It varies, but a large pizza will generally be 14", 16" or 18". All three sizes seem to be commonly used, although 18" is generally more associated with New Yor

It varies, but a large pizza will generally be 14", 16" or 18". All three sizes seem to be commonly used, although 18" is generally more associated with New York or New York style pizzas; 14" is generally more associated with the big national chains. Diameter of 14" = 35.6cm = an area of 993 cm^2. Diameter of 16" = 40.6cm = an area of 1.3k cm^2. Diameter of 18" = 45.7cm = an area of 1.6k cm^2. And down thread someone from Germany says large pizzas there are 26cm, which would be an area of 531 cm^2. That's less than a third the size of an 18" pizza!