Change the DPI of an Image
Set a JPG or PNG to 300 DPI or any other value; the pixels stay exactly the same
Your files stay with you. Conversion happens inside the browser; no file is ever uploaded to a server.
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How it works
When an application form, a print shop or a photographer asks for a "300 DPI image", what they usually check is the DPI value stored inside the file. Choose your images, pick the new DPI from the list and press Change DPI. The tool rewrites the resolution records in the file header with the new value; because the picture itself is never saved again, the quality does not drop. For example, a 3000 × 2000 pixel phone photo tagged at 72 DPI keeps every pixel when set to 300 DPI, and the result line tells you it now prints at 10.0 × 6.7 in (25.4 × 16.9 cm). Nothing is uploaded; everything happens in your browser.
This tool is also known as change dpi of image, change image dpi online, convert image to 300 dpi, change dpi without changing size, change jpg dpi, png dpi changer, increase dpi of image.
What is DPI?
DPI (dots per inch) is the number that tells a printer how many pixels of an image to fit into each inch of paper. It is stored as a separate record inside the file and does not touch the pixels themselves. A photo 3000 pixels wide prints 10 inches wide when tagged at 300 DPI and about 41.7 inches wide when tagged at 72 DPI, yet the detail in the photo is identical in both cases.
What is Image resolution?
In everyday speech, resolution means two different things: the pixel dimensions of an image (for example 1920 × 1080) and its DPI value. Sharpness on screen depends on the pixel dimensions; the DPI only sets the printed size of those pixels. When someone asks for a "high-resolution photo", look at the unit they give: pixels mean pixel dimensions, DPI means the record this tool changes.
What is the difference between DPI and PPI?
PPI (pixels per inch) is the number of pixels per inch and belongs to the digital image itself; DPI strictly means the number of ink dots a printer lays down per inch. In everyday use and in file headers the two are used interchangeably: Windows and most programs show the PPI stored in an image as "DPI", and that is the value this tool changes. A printer's own print resolution (for example 1200 × 1200 dpi) is a separate setting and is not stored in the image file.
Changing the DPI does not make a photo sharper
DPI does not describe the pixels of an image, only how densely they will be laid out on paper. The same 1200 × 800 pixel image prints 12 inches wide at 100 DPI and 4 inches wide at 300 DPI; both prints carry exactly the same amount of detail, only the size changes. That is why raising the DPI never sharpens a blurry photo and barely changes the file size.
If the place asking for "300 DPI" really needs enough detail at a given print size, the pixel count is what matters: a 4 × 6 inch print at 300 DPI needs 1200 × 1800 pixels. If the size in the result line comes out smaller than you need, the image simply does not have enough pixels for that print; lowering the DPI makes the print bigger but adds no detail.
Which DPI value should you pick?
On screen the DPI has no effect at all; phones, browsers and social networks look only at the pixel count. DPI starts to matter when you print, or when you place the image in Word, a PDF or a layout program: those programs size the image according to its DPI by default.
If an organisation, a printer or a form names a specific value, pick that value; your own choice does not replace their rule.
- Photo prints, print shops, application forms → 300 DPI
- Home photo printer → 240-300 DPI
- Posters and large boards seen from a distance → 150 DPI
- Screen use only → no need to change it
Frequently asked questions
Does setting 300 DPI improve the quality of a photo?
No. The pixel count stays the same; the image is only marked to print at a smaller size. The quality does not drop either: the picture is not re-encoded, so JPEG compression is not applied a second time.
How do I change the DPI without changing the image size?
That is exactly what this tool does: the pixel dimensions and the image data are kept as they are, and only the resolution record in the header is rewritten. The file size may change by a few bytes; the picture does not.
Why does my computer not show the new DPI?
A JPEG can store its DPI in several places (JFIF, EXIF, Photoshop and XMP records), and different programs read different ones. The tool writes the same value into every record it finds and adds the missing one. On Windows, right-click the file, open Properties > Details and look at the horizontal and vertical resolution lines; on a Mac, open the file in Preview and use Tools > Show Inspector.
The upload portal asks for 300 DPI — is this enough?
If the portal only checks the DPI record, yes. If it also asks for a minimum number of pixels or a printed size, compare the pixel count and the size in the result line with that; when pixels are missing, changing the DPI alone will not be enough.