Last checked: 24 October 2026. The arithmetic is exact; the size your application asks for is set by the authority you apply to. Informational only, not legal or immigration advice.
A passport or visa photo is specified in millimetres or inches, but an online upload form works in pixels. To get from one to the other you need one extra number: how many pixels fit in one inch (called DPI or PPI).
One inch is exactly 25.4 mm. So:
pixels = millimetres ÷ 25.4 × DPI, or for inches, pixels = inches × DPI.
Round to the nearest whole pixel; a fraction of a pixel cannot exist in the file.
| Printed size | 150 DPI | 300 DPI | 600 DPI |
|---|---|---|---|
| 35 × 45 mm | 207 × 266 | 413 × 531 | 827 × 1063 |
| 2 × 2 in (51 × 51 mm) | 300 × 300 | 600 × 600 | 1200 × 1200 |
| 4 × 6 in (10 × 15 cm) | 600 × 900 | 1200 × 1800 | 2400 × 3600 |
The 2 × 2 in and 4 × 6 in rows are exact (inches × DPI). The 35 × 45 mm row is rounded from the formula above.
For an upload form, mostly no. A web form counts the pixel dimensions (for example “at least 600 × 600”) and the file size in KB. The DPI value stored inside a JPEG is only a label that tells a printer how large to print it. Two files with the same pixel dimensions look identical on screen whatever DPI they carry. DPI matters when you print: at 300 DPI, 413 × 531 px prints at about 35 × 45 mm.
If a form states a size in millimetres and also a pixel range, trust the pixel range for the upload and the millimetres for any printed copy.