Image DPI Converter
Change the DPI value stored inside a JPG or PNG for a print job that checks it, or use the calculator panel to work out DPI, print size or the pixels you need before you have a file.
Drop images here or click to browse
Most image formats up to 50 MB each
Your images never leave your device
Most image formats, up to 50 megabytes each Your images never leave your deviceHow to use the Image DPI Converter
- Upload your JPG or PNG, or use the calculator without a file.
- Choose a new DPI from the chips, or type a custom value.
- Download the file with the new DPI written in, or read your calculator result.
Features
- Reads the current DPI from a file's metadata, or reports not set.
- Common print DPI chips: 72, 96, 150, 300 and 600.
- Optional resample so the physical print size stays the same at the new DPI.
- Calculator tabs for finding DPI, print size or pixels needed.
Does changing DPI change my image's pixel dimensions?
Not by default. DPI only changes the print size a fixed number of pixels represents; a 3000 pixel wide image is still 3000 pixels wide whether it is tagged 72 or 300 DPI. Turn on the resample option if you specifically want the pixel count to change so the physical print size stays fixed at the new DPI.
Why does DPI matter for print but not for a screen?
A screen displays a fixed number of pixels regardless of what DPI value a file claims, so a photo looks identical in a browser or an app whether it is tagged 72 or 300 DPI. Printing is different: the print driver reads the DPI value to decide how large to physically print the pixels you have, which is why a form or a printing service that checks DPI specifically is asking about a value that only matters once ink hits paper.
How is DPI actually stored inside a JPG or PNG file?
A JPEG stores it in a small JFIF header segment near the start of the file, and a PNG stores it in a dedicated chunk called pHYs, each holding a horizontal and vertical value along with a unit. Both are simple enough that a great many tools, including cameras, screenshot utilities and some export dialogs, skip writing anything at all, which is why so many images arrive with no DPI set rather than an incorrect one.
Frequently asked questions
What DPI does print work usually need?
300 DPI is the standard for sharp printed photos and documents. 150 DPI is acceptable for larger prints viewed from a distance, and 72 or 96 DPI is typical for screen only images.
Why does my image show as not set?
Many images, especially ones exported from a web tool or screenshot, never had a DPI value written into their metadata. The image is not damaged; you can set a value with this tool.
Can I calculate print size without uploading a file?
Yes, the calculator panel works from typed numbers alone: width, height and DPI, in any two of which give you the third.
What happens if I turn resample on?
The tool recalculates the pixel dimensions so the image keeps the same physical print size at the new DPI, scaling the actual pixel data up or down rather than only changing the stored metadata value.
Does this tool work on formats other than JPG and PNG?
DPI reading and writing is built specifically for JPEG's JFIF header and PNG's pHYs chunk, so only those two formats are supported for changing DPI.
Can I use this to check a photo before submitting it somewhere?
Yes, upload the file and the tool reports its current DPI immediately, before you change anything, so you can confirm it already meets a form's requirement without guessing.
