A4纸的一半是A5纸，俗称32开纸。尺寸是: 148mm×210mm
纸张类型尺寸:
A1:594mm×840mm
A2:420×594mm
A3:297×420mm
A4:210×297mm
A5:148×210mm
A6:105*148mm
B1:706×1000mm
B2:500×706mm
B3:353×500mm
B4:250×353mm
B5:176×250mm
