Change Image DPI
Forms and printers sometimes ask for a particular DPI. Set it here in two ways: write the new value into the file, or resample the pixels so that the printed size stays the same. Nothing is uploaded.
🔒 Runs in your browser. Your files and text are not uploaded.
How to use the Change Image DPI
- Drop one or more JPG or PNG files on the box, or click it to choose them.
- Choose the Target DPI: 72, 96, 150, 200, 300, 600 or a custom number.
- Choose the Method. “Only change the DPI tag” keeps every pixel as it is; “Resample pixels to keep the same print size” changes the pixel count so the picture still prints at the same size.
- Read the result row, which states the pixel size and DPI, and download the files.
What DPI means, and what it does not
DPI stands for dots per inch, and for digital pictures it really means pixels per inch. A picture is a grid of pixels; DPI tells a printer or layout program how many of those pixels to squeeze into one inch of paper. The printed size is therefore pixels divided by DPI: a 3000-pixel-wide photo prints 10 inches wide at 300 DPI and 41.7 inches wide at 72 DPI.
The DPI number stored in a file is only a hint. It does not change the pixels, the sharpness or, in practice, the file size, and it has no influence on how a picture looks on a screen. That is why a picture at “72 DPI” and one at “300 DPI” can be exactly identical on a monitor, and why a form that asks for 300 DPI is usually checking the pixel size, the tag or both.
Tag only or resample?
| Method | What changes | Use it when |
|---|---|---|
| Only change the DPI tag | The tag in the file. Pixels stay identical, so the printed size changes | A form or program demands a number such as 300 DPI and the pixel size is already fine |
| Resample pixels | The pixel count is scaled so the picture keeps its print size at the new DPI | You must print at an exact size and need the pixels to match, for example a 72 DPI web image that must print at 300 DPI |
Be realistic about resampling. Raising the DPI of a small picture makes more pixels, but the new pixels are interpolated, so the picture does not gain detail, and a 72 DPI web image resampled to 300 DPI will look as soft as before. Lowering the DPI by resampling throws pixels away and makes a smaller file.
Pixels you need for common print sizes
| Print size | At 300 DPI | At 150 DPI |
|---|---|---|
| 4 × 6 in (10 × 15 cm) | 1200 × 1800 | 600 × 900 |
| 5 × 7 in (13 × 18 cm) | 1500 × 2100 | 750 × 1050 |
| 8 × 10 in (20 × 25 cm) | 2400 × 3000 | 1200 × 1500 |
| A4 (210 × 297 mm) | 2480 × 3508 | 1240 × 1754 |
| 35 × 45 mm passport photo | 413 × 531 | 207 × 266 |
| 2 × 2 in passport photo | 600 × 600 | 300 × 300 |
Photographs are normally printed at 300 DPI; 150 DPI is acceptable for drafts and large posters seen from a distance. Scans of text documents are commonly made at 300 DPI, and 600 DPI for fine print. See DPI and print size explained for more.
How to check the DPI of a picture
On Windows, right-click the file, choose Properties, open the Details tab and look under Image for the horizontal and vertical resolution. On a Mac, open the picture in Preview and choose Tools, then Adjust Size. This tool also reports the DPI it found on each result row. JPEG and PNG can carry a DPI tag; other formats are converted to PNG so the tag can be stored, and the result row tells you when that happens.
Frequently asked questions
Does changing the DPI change the image quality?
Changing only the tag does not touch the pixels, so quality is unchanged. Resampling creates a new pixel grid, which can soften the picture when it is enlarged.
How do I convert 72 DPI to 300 DPI?
To satisfy a form that checks the tag, choose 300 and “Only change the DPI tag”. To print a web image at an exact size, choose “Resample pixels”, but note that the picture will not gain detail.
Does DPI matter for images on a website?
No. Browsers ignore DPI and look only at pixels. A 72 DPI and a 300 DPI file with the same pixels look identical on screen.
Why does the tool say 72 DPI was assumed?
Some files have no DPI tag. When resampling, the tool assumes 72 DPI for them and says so on the result row.
Are my pictures uploaded?
No. Everything happens in your browser.