a3 paper size

The size of a3 paper is a half a2 or 2 x a4.

Size of paper a3

  • A3 paper size in millimetres is 297 mm x 420 mm.
  • A3 paper size in inches is 11.7 in x 16.5 in.

A3 Paper Size in millimetres A3 Paper Size in inches

Envelopes for a3 paper

  • For an unfolded a3 you will need an c3 envelope.
  • Fold the a3 paper once – c4 envelope.

More A papers formats

See all paper sizes in A series.