How long is the edge of the grid for writing brush characters?

Usually sold in stationery stores, students use capital letters, commonly used in Mi Zige. The side length of a square is 5 cm to 7 cm.

In lowercase letters, it is a space. Each grid, 1.5 cm to 2 cm.

If the size of brush calligraphy is larger than 10 cm square, such as household couplets, it can be marked as 20-50 ㎝ square.