Click to upload or drag & drop a photo
Processed entirely in your browser — nothing is uploadedCommon millimetre sizes
Millimetre-based sizing shows up most often for UK and EU passport and ID photos, which are frequently specified as 35mm × 45mm. If that's what you need, our dedicated passport photo tool already has that preset built in; use this page for any other custom millimetre size a form might specify.
How to use Resize Image in Millimetres
- Upload your photo, then set the target size, ratio, or preset this page asks for.
- The tool centres and crops (or resizes) your photo automatically to match.
- Review the result in the preview panel — adjust the settings again if it needs a tweak.
- Download the finished file once it looks right.
Tips for best results
- Use a photo where your subject is roughly centred — automatic cropping trims evenly from the edges, so an off-centre subject can get cut.
- For anything going to print, 300 DPI is the safest default unless your form says otherwise.
- If a form specifies both a physical size and a file-size limit, resize first, then compress the result to hit both requirements.
❓ Frequently asked questions
Can I undo a resize after downloading?
Downloading doesn't change your original file — keep it if you want to try a different size later.
Does this work with PNG and WEBP files too, not just JPG?
Yes — you can upload any common image format; the result downloads as a JPG unless the tool says otherwise.
What's the standard UK passport photo size in mm?
35mm × 45mm is the standard UK passport photo size; our passport photo maker has this as a ready preset.
What DPI should I choose?
300 DPI is standard for sharp print-quality photos; use a lower value only if a form specifically asks for it.
Can I switch to centimetres or inches instead?
Yes — see our centimetre and inch resize tools.