In this article
You order a print to hang on the wall or a poster for your shop, and it comes back blurry with jagged edges, even though it looked sharp on your phone. The reason: screens and paper handle resolution in two different ways.
Pixels are what matter
A digital image has a fixed number of pixels, such as 3000 × 2000. That number is the real information in the image. DPI (dots per inch) is just an instruction: how many pixels to place in each inch when printing.
The simple formula
Print size in inches = pixels ÷ DPI (1 inch = 2.54 cm)
Example: an image 3000 pixels wide printed at 300 DPI → 10 inches ≈ 25.4 cm.
How much DPI do you need?
| Use | Suggested resolution |
|---|---|
| Photos and prints viewed up close | 300 DPI |
| Posters viewed from a meter or more | 150 DPI |
| Large billboards viewed from afar | Much lower |
| Screens and websites | DPI is irrelevant; pixel dimensions matter |
Practical examples at 300 DPI
| Print size | Approx. pixels needed |
|---|---|
| 4 × 6 in (10 × 15 cm) | 1181 × 1772 |
| A4 (21 × 29.7 cm) | 2480 × 3508 |
| A3 (29.7 × 42 cm) | 3508 × 4961 |
A common myth
Changing the DPI value in an image’s properties from 72 to 300 without changing the pixels doesn’t improve quality at all; it only changes the suggested print size. If there aren’t enough pixels, the fix is a larger original, or AI enlargement with the Image Upscaler, accepting its limits.
For screens: shrink, don’t enlarge
On websites and stores the problem is the opposite: huge camera images slow pages down. A width of 1200–2000 pixels is enough for most uses. Use the Image Resizer, then the Image Compressor.
Before sending a file to the printer
- Ask the print shop for the required size, resolution and bleed.
- Send a PDF or high-quality image; you can convert images with JPG to PDF.
- Remember that colors on paper look slightly darker than on a backlit screen.
Bottom line
Pixels are the real quality; DPI decides how they spread on paper. For close-up prints, calculate at 300 DPI; for the web, focus on pixel dimensions and file size.
