Calculate DPI, PPI for print and display resolution
What is the DPI Calculator?
The dpi works like this: it derives the DPI/PPI of a display or print from physical dimensions and pixel count. Everything happens on your device - the input never leaves your tab unless the tool clearly states it performs a server-side lookup.
How to use the DPI Calculator
Select or drop your image.
Adjust the available settings while watching the preview.
Check dimensions, quality and format before exporting.
Download the result and keep the original when quality matters.
Features
Runs on your device via the Canvas and WebAssembly APIs
Batch-friendly when you have several files
Original images stay untouched
Common mistakes to avoid
Over-compressing images that contain small text
Exporting transparency to JPEG
Examples
Input
Result
300×400px printed at 3×4 inches
Exactly 100 DPI - comfortably below the 300 print standard
Best used for
Getting a reliable answer for dpi without installing an app
One-off tasks done in under a minute from any device
Checking results before committing them to something important
Working on a phone where desktop software is unavailable
Privacy
Images are processed on your device; nothing is uploaded unless a tool explicitly says a server lookup is involved.
Frequently asked questions
What DPI do I need for print?
300 for paper at reading distance; 150-200 is acceptable for posters viewed from afar.
How do I compute a display's real DPI?
Enter the screen's physical diagonal in inches and its pixel resolution - the pixels-per-inch figure falls out, which tells you how sharp that display really is.
Can I calculate DPI from width and height alone?
You also need the diagonal - the tool accepts the screen dimensions and does the Pythagorean step for you.