In short
A photo measuring 4032 × 3024 pixels has about 12.2 million pixels, or roughly 12 megapixels. More pixels alone don't guarantee a good picture, though: lens, light and processing matter too.
For printing, what counts is how many pixels fit into one inch, measured in ppi (pixels per inch). A common guideline is 300 ppi for prints up to A4 (roughly US letter size) and 200 ppi for larger formats (PhotoReview). The maths is simple: pixels ÷ ppi = inches. The megapixel figure, by the way, is just width times height divided by a million.
Photo: Vitaly Gariev / Unsplash
Example
That 12-megapixel photo prints at about 13.4 × 10 inches (34 × 26 cm) at 300 ppi. A resized 1280 × 960 version only manages about 4.3 × 3.2 inches (11 × 8 cm) at the same sharpness. That might still work for a small photo book picture, but not for a framed poster.
What to watch out for
- Every time a photo is scaled down, for example when it's sent through a chat app, its resolution drops for good.
- Upscaling on a computer afterwards doesn't create real new detail; it only makes the file bigger.
- For a photo book or large prints, always use original quality files. For sharing tips, see How to share wedding photos.
