The inch of pizza refers to inches, 1 inch =2.54 cm.

So 6 inches is 6*2.54= 15.24 cm.

9 inches is 9*2.54=22.86 centimeters.

12 inch is 12*2.54=30.48 cm.

14 inch is 14*2.54=35.56 cm.

Another 9-inch pizza, recommended for 1-2 people, 12 inch pizza, recommended for 2-3 people, 14 inch pizza and above, recommended for 3-4 people or more.

Extended data:

The history of pizza:

Pizza comes from bread, and bread plays an important role as a staple food in western history. It is not always the same in the long flow of time, but by adding different ingredients to better meet people's needs and hobbies. Historians discovered a similar transitional food from bread to pizza 3000 years ago in Sardinia, Italy.

Cake bread π λ α κ ο appeared many times in ancient Greece. (plakous, and π λ α κ ο? ντο? -plakountos) added all kinds of spices, including garlic and onion. And Persians, a king named Dario il Grande (521-486a.c.) baked a kind of' flat bread' with stones, and cheese was added to it.

In the western poem Eneide, there are also the earliest transitional things, which are generally called "focaccia" (meaning baked with fire), "coca" (both salty and sweet) in the west, "pita" in Greek and Italian or "pide" in Turkish, and "piadina" in Romagne. Then there are similar foods in other countries.

Baidu Encyclopedia-Pizza