Passport Photo Size Requirements, Explained

Passport photo specifications look fussy until you understand what they are for. Then they make sense, and reading a new country's rules takes about a minute.

Every specification has two parts

A passport photo specification always tells you two separate things:

1. The physical size of the photo — for example 35 × 45 mm, or 2 × 2 inches.
2. How large your head must appear inside it — usually as a chin-to-crown measurement, sometimes as a percentage of the frame height.

People routinely get the first right and the second wrong. A correctly sized photo where your head is too small is still rejected, because the second measurement is the one that actually matters.

Why head height is the real requirement

Border systems compare faces automatically. The software needs a predictable number of pixels across the features it measures — eye separation, nose width, jaw shape. If heads appeared at wildly different sizes between photos, that comparison degrades.

So the head height rule is not bureaucratic fussiness. It is the requirement that makes the photo usable, which is why it is enforced strictly.

The common formats

35 × 45 mm

The most widely used format, including across the UK, most of Europe, Australia, India and New Zealand. Head height typically falls between 29 and 34 mm, though the exact band varies by country.

2 × 2 inches (51 × 51 mm)

Used by the United States and several countries that follow its convention. Because the frame is square, the composition is noticeably different from the 35 × 45 format — you cannot simply crop one from the other. Head height is generally 1 to 1 3/8 inches.

Other sizes

Canada uses 50 × 70 mm with a 31–36 mm head. China uses 33 × 48 mm. Various national ID cards, driving licences and student cards each have their own. There is no universal standard, only conventions that cluster.

Digital requirements are a separate set of rules

If you are applying online, physical dimensions may not appear at all. Instead you will see:

• Minimum pixel dimensions — often 600 × 600 or larger.
• A maximum file size — commonly a few hundred kilobytes to a couple of megabytes.
• A required format — nearly always JPEG.
• A minimum quality bar — no visible compression artefacts, in focus, correctly exposed.

The mistake here is compressing a photo until it fits the file size limit and pushing it past the quality bar in the process. Resize the dimensions first; only then compress.

Reading a specification you have not seen before

Work through it in this order and you will not miss anything:

1. Overall dimensions, and whether they are given in millimetres, inches or pixels.
2. Head height, and whether it is measured chin-to-crown or as a percentage of frame height.
3. Position of the eyes — some specifications fix how far the eye line sits from the bottom edge.
4. Background colour.
5. Rules on expression, glasses and head coverings.
6. How recent the photo must be — six months is common.

Picking your document type in Passport Photo ID Maker applies the first two automatically, which removes the arithmetic. The rest are still yours to check.

A note on cropping between formats

You cannot reliably crop a 2 × 2 inch US photo down from a 35 × 45 mm one. The aspect ratios differ, and the head height rules differ, so you would be pulling a square out of a rectangle and hoping. If you need two formats, re-crop from the original full-resolution photo each time.

If you are shooting the photo now, see how to make a passport photo on your iPhone first — the framing advice there makes the cropping stage much easier.