What Is DPI vs PPI?
DPI and PPI are often confused, but they serve different purposes. PPI measures screen density, while DPI is used for print output.
Key Dimensions and Reference Table
Use the reference table below as your starting point. These values are designed to fit common platform requirements and prevent cropping or unexpected compression. When possible, export at the exact dimensions for maximum clarity.
If you are unsure about format choice, default to JPEG or WebP for photos and PNG for text-heavy graphics. The right format keeps files lightweight without blurring edges or flattening gradients. When a platform supports modern formats, WebP is usually the fastest option.
A reliable workflow is to resize from the original high-resolution file, export once at the target size, and then upload. Repeated resizing or re-compressing the same file compounds artifacts and reduces clarity over time.
| Term | Definition | Typical Use | Common Values |
|---|---|---|---|
| PPI | Pixels per inch | Screens | 72-300 |
| DPI | Dots per inch | Printers | 300-600 |
| Pixel dimensions | Image size | Web and print | 800-4000px |
| Print size | Physical output | Print workflows | 4x6, 8x10 |
Why PPI Matters
PPI defines how sharp an image appears on screens. Higher PPI means more pixels in a smaller space, which looks crisper.
For web images, PPI is less important than pixel dimensions, since browsers render based on pixels.
Why DPI Matters
DPI controls how printers place ink on paper. Higher DPI produces more detailed prints.
When preparing print files, choose the final print size and target 300 DPI for quality.
How to Choose Correct Settings
Start with the output destination. If the image is for web, focus on pixels. If for print, calculate pixel dimensions based on the physical size and DPI.
Use resizing tools to adjust dimensions without distorting the aspect ratio.
Quality and Compression Tips
Start with the highest-quality source image, resize to the final dimensions, and then adjust compression. This keeps edges clean and prevents the muddy look that happens when files are compressed repeatedly. If your image contains text, use PNG or a high-quality JPEG to keep characters sharp.
For photos, WebP or JPEG at 80-90% quality is usually the best balance of size and clarity. For graphics or logos, use lossless PNG. Always preview the final export at 100% before uploading.
- Resize first, compress second.
- Match the target aspect ratio to avoid cropping.
- Export once to prevent cumulative artifacts.
- Use sRGB color for consistent display across devices.
Practical Examples
A 3000 x 2000 image at 300 DPI prints at 10 x 6.7 inches. The same image on a website could be resized to 1200 x 800 without visible loss.
Common Mistakes
- Changing DPI without adjusting pixel dimensions.
- Using low DPI for print and getting soft output.
- Confusing PPI settings with actual image size.
Related Guides
image resolution explained, aspect ratio explained, resize without losing quality. Return to the PixelPerfect Resizer homepage to resize your images.
FAQ
What is the difference between DPI and PPI?
PPI is for screen density, DPI is for print output.
Does PPI affect web images?
Not much. Pixel dimensions are what matter for web display.
What DPI should I use for print?
300 DPI is the standard for high-quality prints.
Can I change DPI without resizing?
Yes, but it will not change the actual pixel dimensions.
Why does DPI matter for posters?
Large prints need enough DPI to stay sharp at close range.
Is 72 DPI too low?
For print, yes. For web, DPI is less relevant.
How do I calculate print size?
Divide pixel dimensions by DPI to get inches.
Where can I resize for print?
Use PixelPerfect Resizer to adjust dimensions precisely.