What dpi a poster should be, by size and viewing distance
Not always 300. The right number depends on how far away people stand, and a big poster at 300 dpi is a file nobody needs. The table for every common size at 150 and 300 dpi, the limits that matter, and a calculator.
Beginner4 min readUpdated 27 September 2026Editor · Print presets
The table
| Size | mm | At 150 dpi | At 300 dpi | Read from |
|---|---|---|---|---|
| A4 | 210 × 297 | 1240 × 1754 | 2480 × 3508 | Arm's length: use 300 |
| A3 | 297 × 420 | 1754 × 2480 | 3508 × 4961 | Close: use 300 |
| A2 | 420 × 594 | 2480 × 3508 | 4961 × 7016 | A metre or so: 150 to 300 |
| A1 | 594 × 841 | 3508 × 4967 | 7016 × 9933 | Across a room: 150 |
| A0 | 841 × 1189 | 4967 × 7022 | 9933 × 14043 | Across a room: 150 or less |
| 18 × 24 in | 457 × 610 | 2700 × 3600 | 5400 × 7200 | A metre or so: either |
| 24 × 36 in | 610 × 914 | 3600 × 5400 | 7200 × 10800 | Across a room: 150 |
The formula: pixels = inches × dpi, and inches = mm ÷ 25.4. So A3 at 300 dpi is 297 ÷ 25.4 × 300 = 3508 px wide. Round up, never down.
Why distance decides
The eye resolves about one minute of arc. At 30 cm that is roughly 300 dots per inch, which is why 300 became the print standard: at reading distance you cannot see the dots. At a metre you resolve about a third of that, so 150 dpi looks as sharp from a metre as 300 does from 30 cm. At three metres, 100 dpi is plenty. A billboard is often printed at 10 to 20 dpi and looks fine from the road. Printing a wall poster at 300 dpi is not wrong; it is a file four times bigger than it needs to be, which is slower to export, slower to upload, and more likely to hit a limit somewhere.
Limits worth knowing
- Imported photos are capped at 4096 px on the long side in the Editor. That is A3 at about 248 dpi, A2 at 175, A1 at 124, all measured on the long side, all fine from their viewing distance. It also means a photo cannot make an A0 poster sharp close up, whatever you do.
- Exports are capped at about 67 million pixels. A1 at 300 dpi is just over that and A0 at 300 is double it; the Editor scales such an export down to fit. Both sizes are right at 150 dpi anyway.
- Text and shapes are vector and are drawn sharp at whatever size you export. Only photos and painted layers have a dpi.
- Very large canvases are slow. Above 8000 px on a side the browser warns you. Work at 150 dpi for big posters and everything is quicker.
How Voidcanvas handles this
The Editor's print presets are A4 and A5 at 300 dpi and Poster 18 × 24 in at 300 dpi (5400 × 7200). For any other size, use the calculator above and enter the pixel size as a custom canvas on the start screen. Any design over 2000 px on its long side exports as a PDF at 300 dpi; a poster made at 150 dpi therefore comes out at half the physical size on the PDF page, so tell the printer the intended size, or export a PNG and state the size in millimetres. Studio's poster format is 2700 × 3600, which is 18 × 24 in at 150 dpi, and its delivery PDF carries the size in mm with bleed and crop marks.
Is 150 dpi good enough for a poster?
Yes for anything read from a metre or more: A2 and larger, 18 × 24 in and larger. Use 300 for A3 and smaller, which people read up close.
Is 72 dpi OK for printing?
Only for very large formats seen from far away (banners, billboards). For a poster it prints soft. Check the photo's pixel size, not the number in the file: a 3000 px wide file labelled 72 dpi is the same image as one labelled 300.
What size is an A3 poster in pixels?
3508 × 4961 px at 300 dpi, 1754 × 2480 at 150 dpi.
Should I add bleed to those numbers?
If the printer asks for it, yes: 3 mm on each side is 36 px at 300 dpi and 18 px at 150 dpi. See How much bleed a print job needs.