A passport photo is the one picture whose rules belong to someone else. This article covers the part that is arithmetic and the part we measured. The rules themselves live on the issuing authority's own page and change there, so we do not repeat them — we point to them.
From millimetres to pixels
Pixels = millimetres ÷ 25.4 × dots per inch. For the two sizes people search for most:
| Printed size | 300 dpi | 600 dpi |
|---|---|---|
| 35×45 mm | 413×531 | 827×1063 |
| 2×2 in (51×51 mm) | 600×600 | 1200×1200 |
A form that asks for pixels has already chosen the resolution for you. A print shop that asks for millimetres needs the resolution from you — 300 dpi is the usual minimum for a sharp print.
What our resizer makes of an ordinary photo
On 23 September 2026 we ran 20 ordinary photos through the resizer's two passport presets (crop from the center, JPEG quality 0.95). File size in KB, smallest / median / largest: 40 / 76 / 135 for 413×531, and 54 / 113 / 219 for 600×600.
The crop is the expensive part. From a landscape photo it kept 52% of the frame for 35×45 mm and 67% for 2×2 in, at the median. So shoot in portrait orientation, from the chest up, with room around the head — then the crop takes away background, not you.
Read the official rules first
Passport and visa offices set their own rules for head size, background, expression and glasses. Many also forbid cutting the photo out of a larger picture or changing it with software, and online applications have their own requirements for pixels and file size. A resizer crops and changes the picture — which is exactly what some rules forbid.
So start at the source: for example, GOV.UK — Get a passport photo for the United Kingdom, or travel.state.gov — Passport photos for the United States. For any other country, look for the passport authority's own page rather than a summary on a photo app's website.
Where the tool does help
- Forms that give an exact size in pixels or millimetres and say nothing against editing — membership cards, student and staff passes, internal paperwork.
- A test print to check the framing before you go to a photo booth.
- A size limit in KB after resizing: run the result through the compressor with a target size.
The presets: 35×45 mm and 2×2 inches. Everything runs in your browser; the photo is not uploaded anywhere.