DPI / PPI Calculator
Enter pixel dimensions and a physical size to find DPI, or work backward from a target DPI to find print size.
Find DPI from size
Find print size from target DPI
About the DPI / PPI Calculator
The DPI/PPI Calculator relates pixels to physical size. Enter the pixel dimensions and the diagonal size of a screen or print to find its pixel density, or enter a target DPI to find the largest print size an image can support. Photographers, designers and anyone buying a monitor or ordering prints can use it.
Pixel density is the diagonal length in pixels divided by the diagonal size in inches. For print, 300 DPI is the usual target for sharp photo quality at close viewing, while posters viewed from a distance can look fine at 150 DPI or lower. A higher density means finer detail; but a low-resolution image cannot gain real detail simply by raising its stated DPI.
How to use it
- To find density, enter width and height in pixels and the diagonal size in inches.
- To find print size, enter the pixel size and the target DPI.
- Read the resulting PPI or the maximum print dimensions.
- Resize or reshoot the image if the print size is too small.
Tips and good to know
- DPI is a print term and PPI is a screen term, though people use them interchangeably.
- Check the print provider's recommended resolution.
- Upscaling an image in software does not add detail.
Frequently asked questions
What DPI do I need for a passport photo?
It depends on the country; check the official specification.
Is 72 DPI the standard for web?
Screens display pixels; the DPI metadata has no effect on web display.
Why does a phone look sharper than a monitor?
Phones have much higher pixel density.