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.