How to use
- Choose an image, or drop or paste it. PNG and JPG files show the DPI saved in the file; other formats show the pixel size.
- Read how large the image prints at 300 DPI and at 150 DPI, and check the table to see whether it is sharp enough for a photo print, a letter page or a T-shirt.
- To change the DPI, type a number or pick 72, 150 or 300 and download the copy. The pixels are not touched.
- Use the pixels to inches calculator to plan a design: type the pixels and the DPI to get the print size, or the inches to get the pixels you need.
What DPI really means for an image
A digital image is a grid of pixels. DPI (dots per inch), also called PPI for images, is a number saved in the file that tells a program how many of those pixels to print in each inch. It does not change the pixels themselves. The same 3,000 pixel wide photo prints 10 inches wide at 300 DPI or 41.7 inches wide at 72 DPI, with the same detail spread over a larger area.
That is why the pixel size is what decides print quality. The formula is simple: inches = pixels ÷ DPI. A photo needs 300 pixels for each inch to print sharp up close, so a sharp 8 × 10 inch print needs at least 2,400 × 3,000 pixels.
When to change the DPI, and when it will not help
Print shops and print-on-demand services often ask for 300 DPI files. If your image already has enough pixels for the print size but the file says 72 or 96 DPI, changing the label to 300 is all you need, and it is what this tool does. Because only the label changes, the file keeps its exact quality.
If the image is too small, raising the DPI number only makes it print smaller; it cannot add detail. Use a bigger original instead: the photo from your phone or camera rather than a screenshot or a picture saved from social media.
| Pixels needed at 300 DPI | |
|---|---|
| 4 × 6 in photo | 1,200 × 1,800 |
| 8 × 10 in photo | 2,400 × 3,000 |
| Letter page, 8.5 × 11 in | 2,550 × 3,300 |
| T-shirt print area, 15 × 18 in | 4,500 × 5,400 |
| Hoodie print area, 15 × 17 in | 4,500 × 5,100 |
Files for T-shirts and print on demand
Printify's guide for T-shirt designs asks for a 4500 × 5400 pixel PNG at 300 DPI with a transparent background, which fills the 15 × 18 inch front print area. Check your design here before you upload it: if the T-shirt row says Sharp, the file is large enough. To build a shirt design from a photo and text, try the Custom Photo Shirt Maker, which exports 300 DPI files for both T-shirts and hoodies.
Frequently asked questions
How do I check the DPI of an image?
Choose or drop the image above. The tool reads the DPI saved in PNG and JPG files and shows the pixel size and how large the image prints. On Windows you can also see it under Properties, Details; on a Mac in Preview, Tools, Show Inspector.
Does changing the DPI reduce the quality?
No. This tool only rewrites the DPI number in the file. Every pixel stays the same, so the image looks exactly as before; only the size it prints at changes.
Is 72 DPI bad for printing?
Not by itself. What matters is the pixel count. A large image saved at 72 DPI can be set to 300 DPI and print sharp. A small image cannot, because it does not have enough pixels for the size.
How many pixels are in an inch?
It depends on the DPI you print at: 300 pixels per inch at 300 DPI, 150 at 150 DPI and 72 at 72 DPI. Use the pixels to inches calculator to convert any size.
Are my images uploaded?
No. The image is read and changed in your browser, and the new file is saved straight to your device.
