20-format paper: 206mm× 18 1mm, base paper 787mm× 1092mm, and the format size refers to the actual size of the book format after binding and cutting according to the specified format. According to the national standard, the allowable error of format size is1mm. The format size stipulated by the state is an international standard series, which has been included in the national industry standard GB/T788- 1999 "Format Size of Books and Periodicals".

At present, the format specifications of books and periodicals are mainly series specifications, as follows:

a4( 16k)297mm×2 10mm；

a5(32k)2 10mm× 148mm；

A6 (64k)144mm×105mm.

The size of A3(8k) is not determined, and it is generally 420mm×297mm.

Commonly used format size:

8 format: 374×262mm, small 8 format: 368×260mm；; ;

Large 16 format: 262× 187mm, small 16 format: 260×184 mm;

Big 32 format: 203× 140mm, small 32 format:184×130mm;

Big 64 format:13/kloc-0 /×101mm or130× 99mm; ;

Small 64 format: 127×95mm or 125×92mm.