Photo Size for Passport and Online Forms: Pixels, KB and DPI Explained
← Blog · Updated 8 October 2026
Forms often ask for a photo in centimetres, pixels and kilobytes at the same time. They are three different things.
Pixels (dimensions)
Pixels describe the width and height of the picture on screen, for example 413×531. Resize your photo to those exact numbers with Resize to 413×531.
Centimetres and DPI
A printed size such as 35×45 mm depends on DPI (dots per inch). At 300 DPI, 35×45 mm is about 413×531 pixels. That is why this size is common for passport-style photos.
Kilobytes (file size)
KB is how much space the file takes. A form may limit it to 50, 100 or 200 KB. Reduce it with Compress to 100 KB or a similar tool.
The right order
- Convert to JPG if your photo is HEIC.
- Resize to the pixels required.
- Compress to the KB limit.
Important
Requirements differ by country and by form, including the background and face position. Always follow the instructions published by the authority that asked for the photo.
Questions
Does resizing change the KB size?
Usually yes. Fewer pixels normally means a smaller file.
Can I take the photo with my phone?
Yes. Use the Take photo button, then resize and compress it.