A printed passport photo is measured in millimetres or inches. A photo file is measured in pixels. To go from one to the other you need one more number, the DPI, and then it is a short sum. This guide shows the sum, gives the answer for the common sizes, and lists what online forms ask for.
The sum: millimetres to pixels
DPI means "dots per inch": how many pixels fit into one inch of a print. The steps are:
- Divide the size in millimetres by 25.4 to get inches.
- Multiply the inches by the DPI to get pixels.
Take the usual passport photo, 35 × 45 mm, at 300 DPI:
- Width: 35 ÷ 25.4 = 1.37795 inches, and 1.37795 × 300 = 413.4, which rounds to 413 pixels.
- Height: 45 ÷ 25.4 = 1.77165 inches, and 1.77165 × 300 = 531.496, which rounds to 531 pixels.
So a 35 × 45 mm photo is 413 × 531 pixels at 300 DPI. If the size is already in inches, skip step 1. A 2 × 2 inch photo at 300 DPI is 2 × 300 = 600 × 600 pixels.
Common sizes in pixels
| Photo size | At 300 DPI | At 600 DPI |
|---|---|---|
| 35 × 45 mm | 413 × 531 | 827 × 1063 |
| 35 × 50 mm | 413 × 591 | 827 × 1181 |
| 2 × 2 inch (51 × 51 mm) | 600 × 600 | 1200 × 1200 |
| 50 × 50 mm | 591 × 591 | 1181 × 1181 |
| 50 × 70 mm | 591 × 827 | 1181 × 1654 |
| 40 × 60 mm | 472 × 709 | 945 × 1417 |
| 30 × 40 mm | 354 × 472 | 709 × 945 |
| 4 × 6 inch print sheet | 1200 × 1800 | 2400 × 3600 |
The numbers are rounded to the nearest pixel.
Which DPI to use
300 DPI is the normal choice for a printed photo, and it is sharp enough for a passport photo. Some rules ask for more: the German rule for a passport photo applied for abroad asks for a print made at 600 DPI or more, so SafeResize makes that one at 600 DPI.
For a photo you only upload, the DPI hardly matters. A website counts the pixels, and the DPI saved in the file is usually ignored.
What online forms ask for
Online applications usually skip millimetres and give pixels directly. These are the pixel rules on SafeResize for a few well-known ones:
- US visa (DS-160): square, from 600 × 600 up to 1200 × 1200 pixels.
- US Diversity Visa: square, exactly 600 × 600 pixels.
- UK passport: at least 600 × 750 pixels, with no fixed shape.
- India passport (applied for abroad): 630 × 810 pixels.
- India OCI card: square, from 200 × 200 to 900 × 900 pixels.
- Canada visa: at least 420 × 540 pixels.
- Singapore passport: 400 × 514 pixels for online uploads.
- Japan passport (online): 600 × 730 pixels.
- Saudi Arabia tourist e-visa: square, exactly 200 × 200 pixels.
"At least" means a bigger photo is fine and a smaller one is refused. "Exactly" means the width and height must match. Every country page shows its own rule and its source.
Common mistakes
- Changing the DPI and nothing else. Setting a photo to "300 DPI" in an editor without changing the pixels does not make it sharper, and it does not change what a website sees.
- Scaling a small photo up. A photo that is 200 pixels wide cannot be turned into a sharp 600 pixel photo. Start from the original picture from your phone, which has far more pixels than you need. An enlarger can add pixels but not real detail: enlarge a photo without losing quality explains what it can do, and it is not meant for official photos.
- Stretching to fit. Forcing a photo into a new shape squashes faces. Crop the photo instead, so the shape is right and the face keeps its natural look.
- Scanning a print. The US Diversity Visa rule says to scan a 2 × 2 inch print at 300 pixels per inch, which gives 600 × 600 pixels.
Set the pixels in a minute
Open Resize a photo, choose the photo, and type the size in pixels, millimetres, centimetres or inches. It does the sum for you, saves the DPI in the file, and can keep the file under a KB limit at the same time. There are shortcut pages for common sizes: 35 × 45 mm, 2 × 2 inches and 600 × 600 pixels.
For a real passport or visa photo, use the page for your country instead. It also shows the head-size guide and the background rule, and checks the file size. The full list of print sizes is in passport photo size by country.