Guides · Updated 2026-07-21
Passport photo sizes explained: mm, inches, pixels and DPI
Almost every rejected home-made passport photo comes down to a number: the wrong width, the wrong head height, or a pixel count the upload form silently refuses. This guide explains every number you will meet — what it means, where it comes from, and how to convert between the units different authorities use.
Why 35 x 45 mm is the world's default
Of the countries in our requirements database, the large majority specify 35 x 45 mm. That is not a coincidence. The International Civil Aviation Organization publishes Doc 9303, the standard that defines machine-readable travel documents, and 35 x 45 mm is the format most passport-issuing authorities adopted when biometric passports rolled out worldwide.
The practical upshot: if you are applying for a passport in Europe, most of Asia, Australia, Africa or the Middle East, 35 x 45 mm is almost certainly your size. The exceptions are what catch people out — and there are more of them than most guides admit.
The notable exceptions to the 35 x 45 rule
The United States is the largest exception: it uses a square 2 x 2 inch photo (51 x 51 mm), and the same square format carries over to US visas and most USCIS forms. India uses the same 2 x 2 square for visa and OCI applications, as does Saudi Arabia for many visa categories.
Canada uses 50 x 70 mm — noticeably taller than the international standard, and the single most common size mistake among applicants who assume North America shares one format. Brazil also uses 50 x 70 mm. China uses 33 x 48 mm for both passports and visas. Greece and Lithuania use 40 x 60 mm. Finland uses an unusual 36 x 47 mm. Argentina uses a square 4 x 4 cm. Japan's driver's licence photo is a tiny 24 x 30 mm, and Japanese and Korean résumé photos are 30 x 40 mm.
The lesson: never assume a neighbouring country, or even a different document from the same country, shares a size. Check the specific document you are applying for.
Converting millimetres to inches
One inch is exactly 25.4 mm. So 35 x 45 mm is 1.38 x 1.77 inches, and the US 2 x 2 inch photo is exactly 50.8 x 50.8 mm.
That 50.8 figure matters more than it looks. Many guides round the US photo to '51 x 51 mm', and for a printed photo the 0.2 mm difference is invisible. But if you are generating a digital file and the software converts 51 mm to pixels rather than working from the true 2-inch measurement, you can end up two pixels outside the accepted range on a strict upload form. Our tool stores the exact inch measurement for US-format documents and calculates pixels from that, not from a rounded millimetre value.
What DPI actually means
DPI stands for dots per inch — the number of pixels packed into each inch of printed output. It is a relationship between the digital file and the physical print, not a property of the photo on its own.
The formula is simple: pixels = inches x DPI. A 2 x 2 inch photo at 300 DPI is 600 x 600 pixels. The same 600 x 600 pixel file printed at 600 DPI would come out 1 x 1 inch — physically half the size, and rejected.
300 DPI is the near-universal minimum for printed passport photos, and it is what most authorities assume. Some go higher: New Zealand's digital submission requires at least 900 x 1200 pixels, which for a 35 x 45 mm photo means printing at roughly 720 DPI to hit that pixel count.
Why your printed photo can come out the wrong size
Here is a failure mode almost nobody warns about. A JPEG saved by a web browser or a basic image editor often carries no physical density information at all. When you send that file to a print shop and choose 'print at actual size', the machine has to guess — and different machines guess differently. Your photo comes back at 90% or 110% of the size you intended, and it is rejected for dimensions even though the pixel count was perfect.
The fix is that the file itself must declare its density. A properly generated passport photo writes the DPI value into the JPEG header, so the printer knows that this 600 x 600 pixel image is meant to be exactly 2 x 2 inches. If you are generating photos with a general-purpose tool, check the exported file rather than assuming.
Head height: the number that fails most often
Every authority specifies not just the photo size but how much of it your head must occupy — usually measured from the bottom of your chin to the top of your head, including hair.
For the US, that band is 1 to 1 3/8 inches (roughly 25 to 35 mm) within a 2-inch-tall photo, which works out to about 50–69% of the image height. For most 35 x 45 mm formats it is 32 to 36 mm, or roughly 70–80% of the height. The UK is stricter and lower: 29 to 34 mm. Switzerland allows a wider 29 to 36 mm band.
Notice that these do not overlap cleanly. A photo cropped perfectly for a US passport has the head sitting far lower in the frame than a European photo. You cannot crop one file to both standards — which is why 'reuse my old passport photo for a visa' so often fails.
Digital submission: pixel ranges, not just minimums
Online application portals frequently specify a pixel range rather than a floor, and being too large fails just as hard as being too small. China's visa system expects roughly 354–420 pixels wide by 472–560 high. The US DS-160 form requires a square image between 600 x 600 and 1200 x 1200 pixels. Canada's IRCC digital photos need at least 420 x 540. India's e-Visa wants a square image of at least 350 x 350 pixels as a JPEG under 1 MB.
This is why picking a sensible DPI matters for digital submissions specifically. Printing at 300 DPI is the safe default for paper, but for a portal with an upper pixel bound you sometimes need to generate at a lower or higher density to land inside the window.
The 4 x 6 inch print sheet trick
You almost never want to print a single passport photo. Photo labs, pharmacy kiosks and home printers are all built around standard photo paper sizes, and 4 x 6 inches (10 x 15 cm) is the cheapest and most universally available.
The standard approach is to lay several copies of your correctly-sized photo onto one 4 x 6 sheet with cutting guides, print that single sheet at any kiosk for well under a dollar, and cut out the copies you need. This is exactly what commercial passport photo services do behind the counter. It also gives you spares, which matters because many applications require two identical photos.
A quick self-check before you submit
Confirm the size against the specific document, not the country. Confirm whether you need a printed photo, a digital upload, or both — many countries now capture biometrics on-site but still require a photo for the paper form or for visa applications.
For digital uploads, check the pixel dimensions against the portal's stated range and the file size against its limit. For prints, check that the file declares its DPI and that you are printing at actual size with any 'fit to page' or 'auto-enhance' option switched off — auto-enhance can crop or colour-shift your photo just enough to fail.
Where these numbers come from
Understanding the source helps you judge conflicting information online. ICAO Doc 9303 is the international specification for machine-readable travel documents, maintained by a United Nations agency. It defines what a passport photo must achieve technically — a face captured at sufficient resolution, evenly lit, with a determinate outline against the background — so that automated border systems can match it reliably.
Individual countries then publish their own implementation of that standard. Most adopt 35 x 45 mm with a 70–80% head height because that satisfies Doc 9303 comfortably. Countries with legacy formats predating biometric passports, like the US 2 x 2 inch and Canada's 50 x 70 mm, kept their existing sizes and specified head heights that meet the same underlying technical goal by a different route.
This is why you should always prefer the issuing authority's own published requirement over a third-party summary. Where a country publishes no bespoke rule of its own, citing the ICAO standard is the honest fallback — and it is what our requirements database does rather than inventing a country-specific number.
Size mistakes that cluster by region
Certain errors repeat by geography. North American applicants routinely assume Canada shares the US 2 x 2 square; it does not, and 50 x 70 mm is dramatically different. European applicants applying for a Greek or Lithuanian document bring a 35 x 45 mm photo to a 40 x 60 mm requirement, because every neighbouring country uses the smaller format.
Applicants in the Gulf frequently encounter 4 x 6 cm requirements — Egypt, Oman and Qatar's 38 x 48 mm all diverge from the 35 x 45 mm assumption. And anyone dealing with Japanese or Korean documents beyond the passport encounters a genuinely different size for almost every document type.
If you are applying for anything other than your own country's passport, verify the number rather than assuming. It takes seconds and is the single highest-value check you can make.
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