Change Image DPI

How to Use the Change Image DPI Tool

In the first step, upload one JPEG, PNG, or WebP file. The tool supports a single image, so if you have several files, change the DPI in each one separately.

Then enter the new DPI. The default is 300, and the allowed range is 1-2400. You can also use presets for common values: 72, 150, 300, and 600.

Click Change DPI and Download. After a moment, you will get the result: dimensions in pixels, the DPI before and after, the print size in centimeters at the new DPI, and a table for 72, 150, 300, and 600 DPI.

You can download the output file right away. For JPEG, you get a JPEG; for PNG, you get a PNG; and for WebP, you get a PNG with an appropriate note. Processing happens locally in your browser.

What Changing DPI Actually Does

DPI is information about print density that tells programs and printers how large the print should be. It is not a pixel count and does not change the image content itself.

When you change the DPI, the tool saves the new value in the file metadata. The pixel count stays the same, so the image does not become sharper or more detailed. No new pixels appear either.

The effect is mainly visible in print size. With the same file, a higher DPI means a smaller print in centimeters, and a lower DPI means a larger print. On screen, the image still has the same pixel dimensions.

The tool shows the DPI before and after. If the file has no saved DPI, you will see a note that it is missing. For WebP, the reading applies to the file after conversion to PNG, which matters for files that do not store this information in the same way.

How to Calculate Print Size in Centimeters

To calculate print size yourself, use this formula: width in cm = width in pixels / DPI x 2.54. For height, do the same and substitute the height in pixels.

If the image has a certain number of pixels, divide that number by the selected DPI, then multiply by 2.54. The result tells you how many centimeters the print will be, assuming the program or printer respects the saved DPI.

The tool does this for you. After you change the DPI, it shows the print size in centimeters for the new value and a table for 72, 150, 300, and 600 DPI. This lets you quickly compare how the print will change with different settings.

Keep in mind that these calculations are about physical size. They do not change the pixel count or improve image quality. They are just a conversion based on pixels and DPI.

Differences in How JPEG, PNG, and WebP Store DPI

Image formats differ in how they store DPI information. JPEG often stores this value in metadata, so the tool can read the old DPI and save a new one. If the file does not have this information, the result will show that it is missing.

PNG can also contain physical size information, but not every program uses it. The tool saves PNG as PNG, so the output file format stays the same as the input.

WebP is handled differently. The tool reads the image and saves the result as PNG. For this type of file, a note appears that the saved PNG does not store DPI. This means that if you need a WebP file with a new DPI, this tool will not return it in that format.

Therefore, before using the result in print, publishing, or a specific program, check whether that program reads DPI from the file. This is especially important for PNG and files created from WebP.

Tool Limitations

The most important limitation: the tool does not resample. It does not add or remove pixels, sharpen the image, or improve its quality. It only changes the saved DPI and shows calculations related to print size.

It supports a single JPEG, PNG, or WebP file. You cannot upload multiple files at once or other formats. If you have several images, you must change the DPI in each one separately.

A WebP file will be saved as PNG. This is convenient if you care about preserving the image, but it will not give you a WebP file back. In addition, a note appears with this result that PNG does not store DPI.

Graphics programs, printers, online stores, and platforms may ignore the DPI saved in the file. Some use it to set print size, while others rely only on the pixel count. So after changing DPI, check the print preview or settings in the place where you want to use the image.

You can set DPI in the range 1-2400, and the default value is 300. The tool runs locally in your browser.

Frequently Asked Questions

The tool runs locally in your browser and changes only the DPI metadata; the actual print appearance depends on the program and printer, so check the settings before printing.