Poster sizes come from two families. In the United States, sizes are named in inches, like 18 × 24 or 24 × 36. Most of the world uses the ISO A sizes, where each size is exactly twice the area of the one below it: two A4 sheets make an A3, two A3 make an A2, and so on.
Poster sizes chart
The page counts assume a 0.25 in (6 mm) printer margin and a 0.25 in overlap between sheets, the poster maker's defaults, and use the sheet orientation that needs the fewest pages.
| Poster size | Inches / cm | Letter pages | A4 pages | Pixels for 150 ppi |
|---|---|---|---|---|
| 11 × 17 in Tabloid or ledger: the biggest sheet many office printers take | 11.0 × 17.0 in 28 × 43 cm | 4 (2 × 2) | 3 (1 × 3, landscape) | 1,650 × 2,550 |
| 12 × 18 in Small art print | 12.0 × 18.0 in 30 × 46 cm | 4 (2 × 2) | 4 (2 × 2) | 1,800 × 2,700 |
| 16 × 20 in Classic photo enlargement | 16.0 × 20.0 in 41 × 51 cm | 6 (3 × 2) | 6 (3 × 2) | 2,400 × 3,000 |
| 18 × 24 in Medium poster, common frame size | 18.0 × 24.0 in 46 × 61 cm | 8 (2 × 4, landscape) | 8 (2 × 4, landscape) | 2,700 × 3,600 |
| 20 × 30 in Large photo print | 20.0 × 30.0 in 51 × 76 cm | 8 (2 × 4, landscape) | 8 (2 × 4, landscape) | 3,000 × 4,500 |
| 24 × 36 in Standard large poster | 24.0 × 36.0 in 61 × 91 cm | 15 (3 × 5, landscape) | 15 (3 × 5, landscape) | 3,600 × 5,400 |
| 27 × 40 in Movie poster (one sheet) | 27.0 × 40.0 in 69 × 102 cm | 16 (4 × 4) | 16 (4 × 4) | 4,050 × 6,000 |
| A3 297 × 420 mm | 11.7 × 16.5 in 30 × 42 cm | 4 (2 × 2) | 4 (2 × 2) | 1,754 × 2,480 |
| A2 420 × 594 mm | 16.5 × 23.4 in 42 × 59 cm | 6 (2 × 3, landscape) | 8 (2 × 4, landscape) | 2,480 × 3,508 |
| A1 594 × 841 mm | 23.4 × 33.1 in 59 × 84 cm | 12 (3 × 4) | 15 (3 × 5, landscape) | 3,508 × 4,967 |
| A0 841 × 1189 mm | 33.1 × 46.8 in 84 × 119 cm | 25 (5 × 5) | 25 (5 × 5) | 4,967 × 7,022 |
The last column tells you how big your picture should be in pixels to look sharp even up close. Posters seen from a few feet away can do with about half that; see what resolution a big print needs.
Which size should you choose?
- 18 × 24 in is a good first poster: big enough to fill a spot on a wall and only eight Letter pages.
- 24 × 36 in is the standard large poster and fits most ready-made poster frames.
- 27 × 40 in is the movie poster size, if you want to frame it in a cinema-style frame.
- A2 and A1 are the usual sizes for art prints and frames outside the US.
Picture shape matters as much as size
Each size has its own shape. 24 × 36 is a 2:3 rectangle, the same shape as most camera photos. 18 × 24 is 3:4, the shape of most phone photos. 16 × 20 is 4:5, a little squarer. A sizes all have the same long and thin shape (1:1.41).
If your picture has a different shape from the poster size, crop it first so nothing important is cut off later. The poster maker keeps the shape of your picture, so to hit an exact size, choose "Exact width" and type the width you want; the height follows from the picture.
Where to print bigger sizes
Every size in the chart can be printed at home as a tiled poster. If you want one single sheet instead, print shops and office supply stores print up to 24 × 36 in or more on large-format printers, and engineering prints (black and white on plain paper) are a cheap option for big line drawings and maps.