Free tool
Poster Print Quality Checker
Upload an image to check whether it is suitable for printing at A5, A4, A3, A2 or A1. The check runs entirely in your browser - your image is never uploaded or stored.
How poster print quality works
Every digital image is made of pixels. When you print it, those pixels are spread across the paper - the more pixels you have for a given size, the sharper the print. That density is measured in DPI (dots per inch).
Larger posters need more pixels for the same sharpness, but they also hang on a wall and are viewed from further away. That is why an image that looks soft on a hand-held A5 can still look great at A2 - your eye simply cannot resolve the fine detail from across the room. Our checker uses size-aware thresholds, the same ones our poster editor uses, so the answer here matches the answer you would see at checkout.
This works for phone photos, digital artwork and AI-generated images alike. For AI artwork, download the original file from your AI tool rather than a screenshot or chat preview - those are heavily compressed. We accept JPG, PNG or WebP files.
The checker is guidance, not a guarantee: paper, lighting and subject matter all play a part. But if a size is marked Sharp or Suitable here, you can order it with confidence.
FAQ
What resolution do I need for an A3 poster?
As a reference, 300 dpi at A3 is 3508 × 4961 px, but you rarely need that much. An A3 poster is usually viewed from arm's length or further, so images from around 2000 px on the long edge generally print well. Upload your image above for an exact answer.
Can I print a low-resolution photo as a poster?
Often yes - just at a smaller size. A photo that would look soft at A1 can still print sharply at A4 or A5. The checker shows the largest size your image supports, so you can choose confidently.
Does an image need to be 300 DPI?
No. 300 dpi is the professional reference for items held up close, like a hand-held A5. Larger posters hang on a wall and are viewed from further away, so they print sharply at much lower effective DPI. Our checker accounts for this per size.
Can I check AI-generated artwork before printing?
Yes. Download the original file from your AI tool (not a screenshot or chat preview) and check it here. AI images are often exported at modest resolutions, so they commonly print best at A4 or A3 unless upscaled.
What is the biggest poster size my image can support?
Upload it above and look for the largest size marked Sharp or Suitable. That is the biggest we would recommend printing it. Sizes marked as printing soft will still work if the poster is viewed from a distance, but fine detail will be less crisp.