DPI and PPI are two of the most confused terms in image editing. People ask for a 300 DPI image for the web, or try to raise DPI to make a photo sharper. Neither makes sense once you know what they mean.
Here is a plain explanation and a quick guide to what to use.
Key Takeaway: Pixel dimensions decide quality. The DPI number is only a label that tells a printer how large to print those pixels.
PPI vs DPI in Plain Language
- PPI (pixels per inch): how densely pixels are packed in an image or on a screen.
- DPI (dots per inch): how many dots of ink a printer uses per inch. People often use the term loosely to mean PPI.
For a digital image, the real size is its width and height in pixels. The DPI value saved in the file is only a hint for print size.
Does Changing DPI Change Quality?
Not by itself. Changing the DPI tag without resizing leaves the same pixels, so sharpness does not change. It only changes how large the image would print. A 3000 x 2000 pixel image is the same photo at 72 DPI or 300 DPI; at 300 DPI it simply prints smaller (10 x 6.7 inches).
What to Use for Web, Social and Print
| Use | What matters |
|---|---|
| Websites and social media | Pixel dimensions (DPI is ignored) |
| Photo prints | About 300 DPI at the final print size |
| Large posters viewed from far away | Lower DPI can be acceptable |
To print at 300 DPI, multiply the print size in inches by 300. An 8 x 10 inch print needs 2400 x 3000 pixels.
If Your Image Is Too Small
Resize carefully and avoid enlarging beyond what the pixels support. You can enlarge modestly with the Upscale tool (see the upscaling guide), or set exact sizes with the Resize tool. For web, keep files light with the compressor and read resizing without losing quality.
Frequently Asked Questions
What is the difference between DPI and PPI?
PPI counts pixels per inch in an image or screen; DPI counts printer dots per inch. In everyday use the two are often mixed up.
What DPI should I use for the web?
DPI does not matter on the web. Only the pixel dimensions count.
Is 300 DPI always required for print?
It is a common target for sharp photo prints. Large posters viewed from a distance can look fine at lower DPI.
Does increasing DPI make an image sharper?
No. Changing the DPI value without adding pixels does not add detail. It only changes the print size.
How many pixels do I need to print 4 x 6 inches?
At 300 DPI, 1200 x 1800 pixels.
Summary: Pixels decide quality; DPI only sets print size. Use pixels = inches x 300 for print and ignore DPI for web. Set exact sizes with the free Resize tool.