8 inch cake diameter 20cm.

In the earliest times, the cake is round, so the cake in the cake store are in "inch" as a unit, the cake "inch" refers to the inch, so generally we say 8 inch cake refers to the diameter of 8 inches round, the standard mold diameter is about 15cm, height is about 5cm. refers to inches, so generally we say 8 inch cake, refers to the diameter of 8 inches round, the diameter of the standard mold is about 15cm, the height of about 5cm.

Cake size comparison table:

6 inches cake (1 lb. cake): suitable for 2-3 people to eat, suitable for birthday parties, Valentine's Day, Mother's Day and other festivals.

8-inch cake (2-pound cake): suitable for 3-5 people, suitable for birthday parties, various festivals, visiting friends and relatives.

10 inch cake (2.5 lb cake): suitable for 5-8 people, suitable for birthday parties, various festivals, visiting friends and relatives.

12-inch cake (3-pound cake): suitable for 8-10 people, suitable for birthday parties, various festivals, visiting friends and relatives.

14-inch cake (4-pound cake): suitable for 10-12 people, suitable for company, classmates gathering.

16 inch cake (5 pounds cake): suitable for more than 12 people, suitable for all kinds of medium-sized celebrations.