Passport & ID Photo Sizes
Millimetres, pixels and kilobytes are three different requirements, and your photo has to satisfy all of them.
Almost every rejected ID photo comes down to arithmetic rather than photography. There are three numbers involved, they are related but not interchangeable, and most tools only handle one of them.
The three requirements
- Physical size — 3×4 cm, 35×45 mm, 2×2 inches. What the printed photograph must measure.
- Resolution — how many pixels make up each printed inch, almost always 300 DPI. This is what converts millimetres into pixels.
- File size — a cap in kilobytes, imposed by whichever portal you are uploading to.
The conversion is simple: millimetres ÷ 25.4 × DPI = pixels. A 35mm width at 300 DPI is 35 ÷ 25.4 × 300 = 413 pixels.
Sizes by country
| Vietnam 3×4 cm | 354 × 472 px at 300 DPI |
|---|---|
| Vietnam 4×6 cm | 472 × 709 px at 300 DPI |
| Schengen visa 35×45 mm | 413 × 531 px at 300 DPI |
| UK passport 35×45 mm | 413 × 531 px at 300 DPI |
| India 35×45 mm | 413 × 531 px at 300 DPI |
| Japan 35×45 mm | 413 × 531 px at 300 DPI |
| US passport / visa 2×2 in | 600 × 600 px at 300 DPI, max 240 KB |
| China visa 33×48 mm | 390 × 567 px at 300 DPI |
| Canada 50×70 mm | 591 × 827 px at 300 DPI |
Requirements do change, and some authorities publish minimum pixel counts as well. Treat this as a starting point and check the page for the country you are applying to.
The rejection nobody expects
You produce a file at exactly 413 × 531 pixels and it still comes back wrong. This is almost always the resolution field.
Pixels alone do not describe a physical size. A 413 × 531 image is 35 × 45 mm at 300 DPI — and 146 × 187 mm at 72 DPI. Identical pixels, wildly different prints. Which one you get depends on a number stored inside the file, and most editors leave it at whatever the source had.
So a print shop receives a photo with the right pixel count, reads 72 DPI, and lays it out four times too large. You can check and fix that number on an existing file with Set image DPI, or produce it correctly in the first place with Passport photo.
Why doing this in three tools fails
The natural approach is to crop somewhere, resize somewhere else, then compress in a third place. It rarely works, because each step undoes the last:
- The cropper outputs whatever pixel size it likes.
- The resizer hits the pixel count but writes 72 DPI.
- The compressor gets it under the cap and strips the resolution again.
You end up cycling. The three constraints have to be satisfied together, in one operation, which is the whole reason the tool here handles all three at once.
What no online tool can decide for you
Sizing is arithmetic; compliance is not. Most authorities also specify how much of the frame your head must fill, a neutral expression, both eyes open and visible, a plain light background, no shadows, and no glasses in many countries now.
A cropping frame with guides helps you position the face, but it cannot judge whether the background is acceptable or whether you were smiling. Read the requirements — they are usually one page and they are specific.
Printing at home or at a shop
To print several on one sheet: make one photo at the correct size and resolution, then place copies in a document sized 4×6 inches and print that at 300 DPI. Because the resolution travels inside each file, every copy comes out the right physical size.
For a shop, send the single correctly sized file and say what physical size you need. Do not send a crop and hope.
Frequently asked questions
My portal wants a file smaller than I can produce
Check the DPI you asked for. Resolution multiplies the pixel count, and pixel count drives file size far more than quality does — 600 DPI produces four times the pixels of 300 DPI. Very few applications need more than 300.
Can I use a phone selfie?
For the pixels, easily — any modern phone has far more than enough. Whether the lighting, background and angle meet the requirements is the harder question.
What about the background?
A background option in a photo tool fills the area around your picture; it does not cut you out from the wall behind you. For a true plain background you need to photograph against one.
Related guides and tools
- Passport photo — all three constraints in one step
- What DPI means for printing — the number that gets ignored
- Compressing to an exact size — when the file cap is the blocker
Summary
Convert with millimetres ÷ 25.4 × DPI, use 300 DPI unless told otherwise, make sure that resolution is written into the file, and check the portal's file size cap. Satisfy the three together rather than one tool at a time, and read the country's rules for everything sizing cannot cover.