A3 prints: the size that fits almost everywhere.

The measurements, exactly

A3 is 29.7 × 42 cm — 297 × 420 mm, or 11.7 × 16.5 inches. It is exactly twice A4 and exactly half A2, which is the whole point of the A series: every size is the same proportion, so a set mixing A4s and A3s still reads as one family.

What A3 fits

Every Australian homewares and framing shop stocks A3 frames, usually in oak, black and white, from about $25 for a basic one to $80 for something solid. A3 also drops into a ready-made mat inside an A2 frame, which is the cheapest way to make a small print look considered — the mat does the work a larger print would have done.

Where it does not fit: American frame sizes. A US 11 × 14 inch frame is not A3, and a print sized for one will not sit in the other without trimming. If you are buying from a US seller, check which system the print is in. There is a full conversion table on the print sizes page.

Where A3 is right, and where it isn't

Right: a hallway, a desk wall, a kitchen nook, a bathroom, beside a door, or as one of three in a row. A3 rewards being seen from a metre or two away, so it belongs in spaces you pass through or sit close to.

Wrong: alone above a three-seater sofa or a queen bed. A single A3 on a large empty wall reads as an accident. Either go up to A2 or A1, or buy three A3s and hang them as a set — three A3s in a row span about 100 cm with gaps, which starts to hold a wall.