The standard A3 paper size is 297 mm × 420 mm.

Quick Scoop

  • In centimeters: 29.7 cm × 42 cm.
  • In inches: about 11.7 in × 16.5 in.
  • Surface area: about 0.125 m² (1/8 of a square meter).
  • Relationship: A3 is half of A2 and double A4.

If you’re designing or printing, these are the dimensions you should set your canvas or page to for true A3 size.

TL;DR: A3 = 297 mm × 420 mm (29.7 cm × 42 cm, 11.7 in × 16.5 in).

Information gathered from public forums or data available on the internet and portrayed here.