Image DPI checker
A file does not have one DPI. It has as many as the sizes you might print it at — the number only exists once you choose a size. This checker takes your pixel dimensions and the size you have in mind, and reports the resolution that actually lands on the press.
Enter your pixel dimensions to see the resolution you would actually get.
| Answers | At the size I want, is there enough detail? |
|---|---|
| You provide | Pixel width and height, plus the print size you intend |
| You get | Horizontal, vertical and limiting DPI, and which edge is the tight one |
| Working target | 300 DPI at final size for work seen close up |
| Engine thresholds | 200 DPI and 150 DPI are where SafeWidth's own decision changes |
| Runs | In your browser. The pixel numbers you type are never sent anywhere |
Why the number moves when the size moves
DPI is dots per inch, so it is a ratio and not a property. The same 3000-pixel-wide file is 300 DPI across ten inches and 100 DPI across thirty. Nothing about the file changed between those two answers; only the question did. This is why 'my image is 300 DPI' is an incomplete sentence, and why the tag stored inside a JPEG is not the measurement — it is a note somebody wrote, and stretching the file does not update it.
Both edges matter, and the smaller one wins
Most calculators divide one number by one number. That is fine for a square, and misleading for everything else. A 3000 × 600 panorama asked to fill a 25 × 25 cm square lands at 305 DPI across and 61 DPI down: the width looks excellent, the height is unusable, and an average of the two would describe a file that does not exist.
- The limiting edge is the one with the lower ratio — it decides what the print looks like
- Keeping the image's own proportions avoids the problem entirely, which is why that is the default here
- If you must fill a fixed frame, something gets cropped or stretched; the checker shows you which edge pays
Is 300 DPI always required?
No, and treating it as a rule wastes files that would have printed. 300 DPI is a working target for artwork examined at reading distance. A garment transfer viewed at arm's length holds together far below it, and a banner read from across a room lower still. What does not change is the direction: less detail is less detail, and no resampling invents the texture that was never captured.
- SafeWidth's engine treats 200 DPI at the requested size as the point where a normal decision becomes possible
- Between 150 and 200 DPI the honest answer is usually a smaller print, not a rejected file
- Below 150 DPI the shortfall shows at any size the file was meant for
What this checker cannot tell you
Resolution is one measurement among several, and it is the one that arithmetic can reach. It says nothing about whether the edges are clean, whether a transparent background is genuinely transparent, whether a logo picked up compression noise on its way through three chat apps, or whether the black is a printable black. Those need the file itself, not its dimensions.
FAQ
- My image says 72 DPI. Is it unusable?
- Probably not. 72 DPI is the default tag most cameras and screenshots carry, and it describes nothing about the pixels. Enter the pixel dimensions instead — that is the only number that reflects the detail actually present.
- Does resizing in Photoshop increase the DPI?
- Changing the DPI field without resampling only rewrites the tag; the pixels are untouched and this checker's answer does not move. Resampling upward adds pixels the camera never recorded, so the tag improves while the detail does not.
- Which number should I trust, horizontal or vertical?
- The limiting one. It is the edge that runs out of detail first, and it is what a viewer will notice.
- Is anything uploaded when I use this?
- No. The calculation is a division performed in your browser. There is no file, no request to our servers and nothing stored — you can check with the network tab open.