Poster sizes in inches — 18x24, 12x16 and what fits where

18x24 inches is the most searched poster size in the US, and 12x16 is the runner-up. Our sizes are metric, so the closest matches are 45x60 cm (17.72 x 23.62 in) and 30x40 cm (11.81 x 15.75 in).

They are close, but they are not identical — and that matters when you buy a frame. The exact gaps are in the table below.

Every size in inches and centimetres

The price index is set with 30x40 cm = 100. It is a ratio, not an amount, so it holds whatever the posters cost.

Size Inches Nearest US frame Gap Price per in², index
30x40 cm 11.81 x 15.75 12x16 5 x 6 mm 100
A3 (29.7x42 cm) 11.69 x 16.54 no clean match 101
40x50 cm 15.75 x 19.69 16x20 6 x 8 mm 73
A2 (42x59.4 cm) 16.54 x 23.39 no clean match 63
45x60 cm 17.72 x 23.62 18x24 7 x 10 mm 61
50x70 cm 19.69 x 27.56 20x28 8 x 11 mm 51

What the gap means in a frame

Every metric size runs 5-11 mm smaller than its nearest US frame. What that means in practice:

  • With a mat, the gap is invisible. The mat overlaps the print by 5-10 mm on each side anyway, so a 45x60 cm print sits correctly in an 18x24 frame with a mat.
  • Without a mat, you will see a thin line of backing board along two edges — about the width of a pencil lead. Some people never notice it; if you would, use a mat.
  • A3 and A2 have no clean US equivalent. A2 is 86 mm short of a 16x20 frame, so it needs either a mat or a metric frame. If you want a frame from a US store, choose 30x40, 40x50, 45x60 or 50x70.

What fits where

  • Above a bed. Aim for the piece to cover two thirds to three quarters of the bed width. Over a queen bed (60 in) that means roughly 40-45 in — so either one 50x70 cm plus space, or three smaller prints in a row.
  • Above a sofa. One 45x60 or 50x70 works above a loveseat. Above a full three-seat sofa, a single poster looks lost — use three, or step up to a gallery wall.
  • On a free wall. 45x60 cm (18x24) is the smallest size that can carry a wall on its own without looking stranded.

Paper

Every size is printed on 200 gsm coated silk with a white border all the way round, produced in Europe and shipped from a US facility. The border means the print can be framed with or without a mat.

Hanging height

The centre of the picture belongs 145-152 cm (57-60 in) above the floor. For a 50x70 that puts the bottom edge around 110 cm (43 in) up. See the full hanging guide.

A caveat

Frame sizes are nominal. An 18x24 frame from one brand is not always the same inside as another — measure the rebate, not the label, if the fit has to be exact. Updated 18 August 2026.