DPI vs Pixels: Image Resolution Explained Clearly
Understand pixels, DPI and PPI, why changing DPI may not change an image on screen, and how to calculate print size.
Pixels describe the image
A 3000 × 2000 image contains six million pixel positions whether its resolution field says 72, 96 or 300. Browsers normally size raster images with CSS and pixel dimensions, not print-density metadata.
Print size is a calculation
At 300 pixels per inch, a 3000-pixel image prints about 10 inches wide. At 150, it covers about 20 inches but may look less sharp close up.
Formula: print inches = pixel dimension ÷ target pixels per inch.
Why changing DPI may do nothing
If an editor changes only metadata without resampling, pixel count and screen appearance stay unchanged; only suggested physical size changes. With resampling, software creates or removes pixels.
Choose by destination
- Website: use rendered pixels and responsive sources.
- Office print: confirm printer needs and viewing distance.
- Professional print: ask for dimensions, bleed, colour and resolution requirements.
Frequently asked questions
Is 72 DPI required for web?
No. Pixel dimensions and file weight normally matter to browser display.
Does 300 DPI improve a small image?
Not alone. Without resampling it changes metadata; with it, pixels are invented.