DPI, dots per inch, is the setting a print shop means when it asks for a photo at 300 DPI. It does not change how your image looks on a screen. It tells a printer how many pixels to squeeze into each inch of paper, which sets how large and how sharp the print comes out. This guide explains what DPI does, when it matters, and how to set it without losing any quality.
TL;DR — Use the change DPI tool to set a JPG or PNG to 300 DPI or any value you need. Set the DPI, read off the print size, and download. The pixels never change, so there is no quality loss.
DPI is a print setting, not a pixel count
Your image has a fixed number of pixels, for example 1800 by 1200. DPI decides how those pixels are spread across the paper:
- At 300 DPI, 1800 pixels print across 6 inches.
- At 150 DPI, the same 1800 pixels spread across 12 inches, so the print is larger but softer.
Nothing about the pixels themselves changes when you set the DPI. You are only writing down the intended print size. That is why setting DPI is lossless: the picture on your screen looks exactly the same before and after.
What DPI should you use?
| Where it prints | Typical DPI |
|---|---|
| Photos and everyday documents | 300 |
| Large posters seen from a distance | 150 |
| Fine art and detailed prints | 600 |
300 is the safe default that most print shops expect. Go higher only when the print will be held close and studied. Go lower when the print is big and viewed from across a room, where the extra dots would never be noticed.
Step by step: change the DPI
- Open the change DPI tool and drop in your JPG or PNG.
- Read the current DPI and pixel size the tool shows for your file.
- Type the DPI you need, such as 300, or tap a preset.
- Check the print size shown in inches and centimetres to make sure it fits your paper.
- Download the image. It is the same picture with an updated print setting, and nothing was uploaded.
Tip: If the print size at 300 DPI comes out smaller than you need, the image simply does not have enough pixels for a larger print at that sharpness. In that case you need a bigger source image, not a higher DPI.
DPI versus resizing
It helps to keep two ideas separate. Changing DPI relabels how big the existing pixels print. Resizing actually adds or removes pixels to change the image itself. For a sharp print you usually want plenty of pixels first, then set the DPI so they land at the size you want on paper.
Where to go next
- Resize an image — change the actual pixel dimensions.
- Compress an image without losing quality — shrink the file size for sharing.
