Posters · Glossary

What DPI does a poster need?

Far less than people assume. A conference board is read from about a metre, not held at reading distance, so roughly 100 pixels per inch at full A0 size is enough for crisp type and clean chart lines. The 300 DPI rule comes from photographic printing, where a viewer can lean in and inspect the surface.

Almost every poster question that starts with resolution is really a question about type size. A board that is hard to read at a metre is rarely fixed by more pixels.

Nuwan Madhusanka · Co-founder

3 min read · Published 31 August 2026

Why 300 DPI is the wrong target

Three hundred dots per inch is the standard for something held at thirty centimetres, like a photograph in a book, because that is roughly the limit of what the eye resolves at that distance. At a metre the eye resolves about a third as much detail. Printing a poster at 300 DPI produces a file several times larger than necessary, slower to handle and slower to print, and no reader can tell the difference.

Work at a smaller canvas, export larger

The practical approach is to design on a canvas that is manageable and export at a multiple of it. An A0 board authored at 50 pixels per inch is 1,656 by 2,340 pixels, which drags and edits smoothly, and exporting at twice that gives 3,312 by 4,680, which lands near 100 pixels per inch at full size. A 300 DPI A0 canvas would be 9,930 by 14,040, which is unpleasant to edit and buys nothing on the wall.

Type size is the real variable

The number that decides whether a poster is readable is the height of the body text, not the resolution of the file. As a rough guide, body text on an A0 board wants to be around 24 point and the title large enough to read from several metres. If you find yourself shrinking text to fit, the fix is less text, not more pixels.

Questions people ask

Will a print shop reject a 100 DPI file?

Some will ask, because their standard quote is written for photographic work. Explain the viewing distance and the full size dimensions in pixels; a file that is 3,312 by 4,680 for an A0 board is exactly what it should be. If they insist, the honest question back is what visible difference they expect at a metre.

Does the file need to be CMYK?

Exports are usually RGB, and most modern printing workflows convert on receipt. Ask your shop rather than converting yourself, because a conversion done without their profile can shift your colours more than leaving it alone would. If colour carries meaning in your figures, ask for a proof.

What about bleed and crop marks?

A poster is normally printed to size and trimmed with a margin, so bleed is rarely needed. If your design runs colour to the very edge, ask the shop what they want before you export, because adding bleed to a file that was not designed for it usually means reflowing the whole board.

Is a PDF or a PNG better for printing?

Either works if the pixel dimensions are right. A PDF that places a single high resolution image per page is effectively the same thing as the PNG inside it, so what matters is the resolution of the image, not the container. Send whichever the shop asks for.

How do I check it will read from a distance?

Print one A4 crop of the busiest area at full scale and pin it up. If the body text on that crop is comfortable at a metre, the board will be. This takes two minutes and catches more problems than any amount of zooming on screen.

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Sources

Written and checked by the OneCraft team. Last checked 31 August 2026.