Convert pixels to cm or inches and change DPI
Work out how big an image prints at a given DPI, or what pixel size you need for a given print size. You can also rewrite the DPI value stored in a JPEG, PNG or TIFF.
Drop images here, or pick them from your device
Stays on your device. Nothing is uploaded.
Processing on this device
How to use it
- Use the calculator: enter pixels and DPI to get centimetres or inches, or the reverse.
- To change a file, add a JPEG, PNG or TIFF.
- Enter the DPI value you want.
- Write it and download. Pixels are not changed.
What it keeps
- Every pixel. Only the DPI value in the file changes.
- Quality and dimensions in pixels.
What it removes or changes
- The stored resolution number changes, which affects the default print size in some programs.
Limits
- DPI alone does not change pixel dimensions or quality. A 72 DPI and a 300 DPI file with the same pixels look identical on screen.
- To get more real detail for print, you need more pixels, which this tool cannot invent.
- Works for JPEG, PNG and TIFF.
Compatibility
Print programs and some upload forms read the DPI value to set size or to judge suitability. Changing the number is quick, but check whether the form wants a pixel size or a DPI value, as they are different things.
Privacy
Calculation and file rewriting happen in your browser. Files are not uploaded.
DPI, PPI and pixel dimensions
Pixel dimensions say how much information an image holds. DPI says how densely those pixels are laid down when printed, so the same pixels print larger at low DPI and smaller at high DPI. Quality for print depends on the pixels available at the size you want, which is why changing only the DPI label can fix a labelling problem but never a quality problem.
Troubleshooting
The form still says the resolution is too low.
It probably checks pixel dimensions. Changing DPI cannot add pixels.
Print size is not what I expect.
Print size equals pixels divided by DPI. Check both numbers.
The file looks the same on screen.
It should. DPI does not affect screen display.
Frequently asked questions
Does changing DPI improve quality?
No. DPI does not change pixel dimensions or visual quality. It only changes the stored print density.
Which formats can I rewrite?
You can rewrite the DPI value in JPEG, PNG and TIFF files without touching the pixels.
Does it resample?
No. Pixels are left exactly as they are. Only the resolution value in the file changes.