Paper basics
Paper dimensions and paper weight are different
A size label tells you the format, not the thickness.
By Printer Paper Size Team•
Two sheets can share the same width and height while feeling very different. A paper size such as A4 describes dimensions. A weight specification such as grams per square meter (gsm) describes mass per area.
Specify both when ordering
An order for “A4 paper” leaves the material unspecified. Include the required format, paper weight and finish. Thickness is another property and cannot be inferred exactly from gsm alone because materials differ.
Check your printer’s supported paper sizes and media weights. A sheet that fits the tray may still be unsuitable for the feed path or selected printing process.