Passport and ID Photo Sizes Explained: mm, Inches, Pixels and DPI
Why photo requirements are given in millimetres or inches, how they convert to pixels, and how to prepare a correctly sized passport or ID photo at home.
Passport, visa and identity card photos are almost always specified as a printed size — for example 35 × 45 mm or 2 × 2 inches — rather than in pixels. When you submit a photo online, that printed size has to be converted into a digital image with the right number of pixels and the right shape. Getting the shape (aspect ratio) right is just as important as getting the size right.
Common photo sizes
The sizes below are widely used, but rules differ between countries and change over time. Always check the official instructions of the authority you are applying to — this table is a starting point, not an official requirement.
| Size | Shape | Pixels at 300 DPI | Where it is commonly used |
|---|---|---|---|
| 35 × 45 mm | Portrait, 7:9 | 413 × 531 px | Passports and visas in many countries |
| 2 × 2 in (51 × 51 mm) | Square | 600 × 600 px | United States passports and visas |
| 25 × 32 mm | Portrait | 295 × 378 px | Some ID cards and licences |
| 50 × 50 mm | Square | 591 × 591 px | Some visa applications |
| 20 × 25 mm | Portrait | 236 × 295 px | Stamp-size photos for forms |
How millimetres become pixels
DPI (dots per inch) links physical size to pixels. At 300 DPI, every inch of the printed photo contains 300 pixels. One inch is 25.4 mm, so a 35 mm wide photo at 300 DPI is 35 ÷ 25.4 × 300 ≈ 413 pixels wide. PhotoSize does this conversion for you and also writes the DPI value into the file, so it prints at the correct physical size.
Tip: If a form gives a size in pixels (for example 200 × 230 px), use pixels directly — DPI does not matter for on-screen use.
Framing the face
- Face the camera directly with a neutral expression and both eyes open.
- Use even lighting with no shadows on the face or the background.
- Use a plain, light background unless the rules say otherwise.
- Leave space above the head — most rules specify how much of the photo the head should fill.
- Remove glasses if the rules require it, and avoid hats or head coverings unless permitted.
Preparing the photo with PhotoSize
- Open the Passport / ID Photo tool and choose a preset, or enter your own size.
- Drag the crop frame so the face is centred; drag a corner to zoom in or out. The frame always keeps the correct shape.
- If the form has a file size limit, switch on "Maximum file size" and enter it.
- Create the photo and check the result: the dimensions should match exactly and show a green check.
You can prepare up to five photos at once — useful for a family application — and each photo keeps its own crop.