Poster frame sizes: standard sizes in cm and inches

Two families of frames

Frames are built around the prints people put in them. In countries that use ISO paper, ranges include sizes cut for A series sheets, such as 21 by 30 centimetres for A4, alongside photo and art sizes such as 30 by 40, 40 by 50, 50 by 70 and 70 by 100. IKEA Australia's frame range, for example, lists 10 by 15, 13 by 18, 21 by 30, 30 by 40, 40 by 50, 50 by 70, 61 by 91 and 70 by 100 centimetres, plus square frames. In North America frames follow inch sizes, and papersizes.org lists 11 by 17, 18 by 24 and 24 by 36 inches as the US small, medium and large posters.

Why A sizes rarely fill an art frame

A series paper has a 1 to 1.414 proportion, but most art frames are 3 to 4 or 5 to 7. A 50 by 70 centimetre frame is 1 to 1.4, very close to A or B proportions, so B2 at 50 by 70.7 centimetres trims to fit almost exactly and A2 sits inside with a mat. A 40 by 50 frame is 4 to 5 and leaves an uneven border around any A size. When the poster and frame proportions do not match, a mat with a custom opening is the usual fix, and it makes the gap look intended rather than accidental.

Mats, borders and glass

A mat, sometimes called a passe partout, is a card border inside the frame. It needs an opening a few millimetres smaller than the print on each side so the edges are covered, and most framers cut one to order. Without a mat, the frame's rebate covers a few millimetres around the edge, so keep text and important detail well inside it. For posters behind glass, matte paper avoids double reflections, and acrylic glazing is lighter and safer for large frames hung in schools or offices.

Common mistakes

The first is buying a 30 by 40 centimetre frame for an A3 poster and finding the poster sits loose with a few millimetres showing on two sides. The second is an inch frame for a millimetre print, such as an 8 by 10 inch frame for A4, which crops it on every side. The third is a full bleed design whose edges disappear under the frame lip. The fourth is ordering the print before measuring the frame, when frames from different makers can differ by a few millimetres.

Printing a poster to fit a frame

The poster tab makes A0 portrait and A0 landscape boards only, so a framed poster is designed at A0 and printed smaller. Because A0, A1 and A2 share one proportion, the A0 export of 3312 by 4680 pixels prints at A1 or A2 with nothing cropped; for a 50 by 70 frame, print at A2 with a mat or ask for a B2 print, which trims to 50 by 70. The print scale calculator gives the percentage to scale any size to any frame, and the paper size converter lists the exact dimensions. The blank PNG above is 3600 by 5400 pixels, a 24 by 36 inch frame at 150 DPI.

Questions people ask