DPI
What DPI means for screenshots, how it affects resolution and file size, and common confusion with PPI.
DPI (dots per inch) measures how many ink or toner dots a printer places in one inch. In everyday use it is also used for PPI (pixels per inch), the number of image pixels mapped to one inch of print or screen.
In an image file, DPI is a metadata value. PNG stores it in the pHYs chunk, JPEG in the JFIF header or EXIF resolution tags. The value tells print and layout software how large to place the image. It does not change the number of pixels.
A 2400 pixel wide image printed at 300 DPI is 8 inches wide. The same file printed at 150 DPI is 16 inches wide and looks softer, but the file itself is identical.
DPI vs PPI
PPI describes pixels in an image or on a display. DPI, strictly, describes printer dots, and a printer may use several dots to reproduce one pixel's color. Software often labels the image resolution field as DPI, which is why the terms are mixed up. For screenshots, the useful number is the pixel width and height.
How DPI affects screenshots
On screen, a screenshot shows at its pixel size, adjusted by the display's scale. The embedded DPI value has no effect in a browser or chat app. Changing it in an editor without resampling leaves file size and sharpness unchanged. What makes a screenshot sharp is the pixel count, which on a Retina display is twice the point size in each direction.
DPI and print vs screen
| Output | What matters | Rule of thumb |
|---|---|---|
| Screen, web, chat | Pixel dimensions | Match or exceed the display size |
| Office print | Pixels per printed inch | About 150-300 PPI |
| PDF documents | Pixels and page size | Enough pixels for the placed width |
A 1600 pixel wide screenshot placed 5.33 inches wide in a PDF prints at 300 PPI.
Common mistakes
- Raising DPI to 300 and expecting a sharper image. Only pixels add detail.
- Upscaling a small screenshot to reach a target DPI.
- Comparing two screenshots by their DPI field instead of their pixel size.
Taking the same screenshots again and again?
Capture a fixed area at the same pixel size every time with screenshot automation on Mac.
Common questions
What DPI do screenshots have?
The field varies by tool and display and has little meaning on screen. Check the pixel dimensions instead with Screenshot Resolution Checker.
Does DPI change file size?
No. File size depends on pixel count, content and compression.
Sources
Related resources
- Documents export: paper size and image sizing in PDF export.
- Screenshot Resolution Checker: read the pixel size of an image.
Taking the same screenshots again and again?
Temposhot captures a screen, window or area on a timer and exports the set as a PDF, images, ZIP or MP4. The free browser tools fix single images.
Related resources
Related terms
- Pixel DensityWhat pixel density means, how it affects screenshot resolution, and common confusion with DPI.
- Retina ScreenshotWhat a Retina screenshot is, why it's 2x the expected size, and how to handle high-DPI captures.
- Screenshot ResolutionA screenshot copies the pixels on screen, so it doesn't lower quality by itself. See what makes screenshots blurry and what decides their size in MB.
- Image ResizeWhat image resizing is, how it differs from cropping, and mistakes to avoid when scaling screenshots.
- Viewport ScreenshotWhat a viewport screenshot is, how it differs from full-page capture, and when it's the right choice.