Print size = pixels ÷ DPI.
Effective DPI = pixels ÷ print inches. We compute it for width and height and report the lower of the two, since that limits sharpness, along with a quality rating.
Dots per inch — how many pixels are packed into each printed inch. Higher means sharper.
300 DPI is the standard for sharp photo prints.
If your image and print aspect ratios differ, each dimension yields a different DPI.
For large prints viewed from a distance, often yes; for handheld photos, aim higher.
Print smaller, or start from a higher-resolution image.