Formulas
Print size (in) = pixels ÷ DPI. Pixels needed = inches × DPI (for centimeters, divide by 2.54 first).
Examples
A 12-megapixel photo (4000 × 3000) prints at 13.33 × 10 in at 300 DPI, or 26.67 × 20 in at 150 DPI.
A 6 × 4 in print at 300 DPI needs 1800 × 1200 pixels, only 2.2 megapixels. Almost any phone photo is enough.
What DPI should I use?
- 300 DPI: photos and printed material seen up close.
- 200 DPI: still sharp for most people.
- 150 DPI or less: posters and banners seen from a distance.
Cropping a photo removes pixels, so check the size again after cropping.
Frequently asked questions
Does changing the DPI in an editor improve the photo?
No. Changing only the DPI number does not add detail; it only changes the print size. Upscaling invents pixels and can look soft.
Is DPI the same as PPI?
For this calculation, yes: it is how many image pixels go into each inch of paper.
See also
Results are estimates for information only and are not financial, legal or medical advice. Rates, taxes and fees vary — confirm with a professional or your lender.