Close viewing favors more pixels
300 PPI is a common high-quality target for books, photos, and small prints seen up close. 240 PPI can still produce strong results with a good source and suitable printer.
Large prints can use lower density
Posters and display graphics are often viewed from farther away, so 150 PPI may be practical. Always check the printer’s specification and inspect the image at the intended size.
Calculate print size from actual pixels
Print width in inches = pixel width ÷ target PPI; height uses the same calculation. Multiply inches by 2.54 for centimeters. A 3000 × 2400 pixel file gives 10 × 8 inches at 300 PPI, 12.5 × 10 inches at 240 PPI, or 20 × 16 inches at 150 PPI. Changing only the stored DPI/PPI tag does not add pixels. These sizes assume no cropping or resampling; focus, compression and viewing distance also affect the result.