Passport photo head size, explained

One vertical measurement, chin to crown

Head size is the distance from the bottom of your chin to the crown of your head, measured vertically inside the finished photo and stated in millimetres. GOV.UK puts it as plainly as anyone: "The image of you - from the crown of your head to your chin - must be between 29mm and 34mm high" (GOV.UK). Every authority that publishes a head size publishes it that way, against its own frame, and the numbers do not agree with each other.

Two things follow immediately. Head size is decided at the crop, not at the camera, so how far you stood back changes your pixel budget rather than your measurement. And a percentage you read on one country's page is worthless on another country's photo, because the frames are different heights.

Where the crown is, and what the hair does

The crown is the top of your head as it appears in the picture. There is nothing else in a photograph for a measurement to end on: a scalp under hair is not visible, and a ruler laid on a print stops at the topmost thing in the frame. On a photo with volume, a quiff or an updo, the hair is the crown, and it pushes the measurement up by however tall the hair is.

Most of the authorities in this set do not spell the hair question out. One does, and it goes the other way: France asks for 32 to 36 mm chin to crown excluding hair, which lands the measurement on a different part of your head than the German or British rule does on identical 35 × 45 mm paper.

A hairstyle change therefore invalidates an old measurement even when nothing else about the photo has changed, which catches people re-cropping a shot from a few years ago. Renewal photos carry recency rules on top: the UK wants a printed photo taken in the last month, and Mexico will not take one more than 30 days old.

The published ranges, side by side

The same person, photographed once, needs a different crop for each of these. The percentage column is the head height as a fraction of the frame height, which is the only way to compare frames of different sizes.

Two neighbours make the point sharpest. The Netherlands allows 26 to 30 mm and Germany 32 to 36 mm, both on 45 mm paper. The ranges do not touch, let alone overlap. The Dutch rules add a second measurement almost nobody expects, a face width of 16 to 20 mm ear to ear (Rijksoverheid), so a Dutch photo can pass on height and fail on width.

Canada sits at the other end: 31 to 36 mm on a 50 × 70 mm frame, or 44 to 51 per cent, the smallest head fraction here (Canada.ca). It also states its two routes in different units, millimetres for the printed photo and 45 to 50 per cent for the digital one, and the two do not land identically. The printed photo has a further problem no crop can solve: it must be taken by a commercial photographer and stamped on the back, so a home print cannot satisfy it. The Canada tool targets the digital specification.

Four authorities here publish no head height at all. If a site shows you a green tick against an Irish, Mexican, Brazilian or Spanish head measurement, it is checking a number it made up. The full size list and passport photo sizes, explained cover the frames themselves.

Why "fill 70 to 80 per cent" is bad advice

That figure is real, and it belongs to Germany. A German head of 32 to 36 mm on a 45 mm frame is 71 to 80 per cent, which is exactly where the number comes from. Italy and Schengen consular practice quote 70 to 80 per cent as well, but for the face rather than chin to crown, which is a different landmark and a smaller distance. Applied anywhere else, the number puts you over the ceiling:

• United States. 70 per cent of 50.8 mm is 35.6 mm, already past the 35 mm maximum. At 80 per cent you are at 40.6 mm, 5.6 mm too tall.
• Netherlands. 70 per cent of 45 mm is 31.5 mm against a 30 mm ceiling; 80 per cent is 36 mm, 6 mm over.
• United Kingdom. 70 per cent lands at 31.5 mm and passes. 80 per cent is 36 mm, 2 mm over the 34 mm limit.
• Canada. 70 per cent of a 70 mm frame is 49 mm against a 36 mm ceiling, 13 mm out.

The advice travels because it sounds like a fact about faces. It is a fact about one country's paper. The error runs the other way too, for anyone copying a US or Canadian crop onto a European frame and ending up with a head too small. Framing is among the most common reasons a photo comes back at all — see the reasons passport photos get rejected.

Measuring a photo you already have

You do not need a physical ruler or a print. Head size is a ratio, and a ratio can be measured in pixels:

head in mm = frame height in mm × (head in pixels ÷ photo height in pixels)

Measure on the final crop, not the original: a percentage means nothing until the frame is fixed. Open it in any editor that shows cursor coordinates, note the pixel row at the bottom of the chin and the row at the top of the hair, and subtract.

• A UK photo, 750 px tall. Chin at row 610, crown at row 120, so the head is 490 px. 45 mm × (490 ÷ 750) = 29.4 mm, just inside the 29–34 mm range. Two millimetres of extra hair would put it out.
• A US photo, 1200 px square. A 700 px head gives 50.8 mm × (700 ÷ 1200) = 29.6 mm, comfortably inside 25–35 mm. Now check the second US rule: eyes 690 px up from the bottom edge give 50.8 × (690 ÷ 1200) = 29.2 mm, inside the required 28 to 35 mm (travel.state.gov). A correctly sized head can still sit too low in the square.

On a print, use a ruler, and measure the photo itself first. If a UK print measures 44 mm rather than 45, the head range shifts with it, and the likeliest cause is a print dialogue set to fit-to-page or a file with no real density written into it. Pixels and DPI and the 4 × 6 sheet deal with that; printing at a pharmacy counter covers the borderless trimming risk on a six-up 2 × 2 layout.

What to do when it is out of range

If the head is too large, recrop wider. That needs spare image around your head, which is why the framing advice for a phone shot is to stand further back than feels right and leave room on all four sides — taking a passport photo with a phone covers it. Scaling the whole picture down does not help, because it shrinks the frame along with the head and the ratio stays where it was.

If the head is too small, crop in, then check what is left. Cropping in throws away pixels, and portals have floors: the UK asks for at least 600 × 750 px, the US visa upload for 600 × 600 to 1200 × 1200 px, Canada for at least 1800 × 1200 px. Cross the floor and you have swapped one rejection for another. File size limits and the DS-160 tool handle the upload end.

If neither crop works, reshoot. That is the honest answer, and it is cheaper than an application that comes back. What you must not do is stretch the image to fit: a distorted face is visible, and the head measurement it produces means nothing. Nor should you reach for a retouching tool. Cropping and resizing are what these authorities ask for; altering the image is a separate act several of them prohibit in their own words, including GOV.UK's requirement that the photo be "unaltered by computer software". The rule that broke every AI passport photo tool sets out each authority's wording.

Two cases sit outside all of this. Babies rarely hold still long enough for a measured crop, and the UK relaxes the expression and eye-contact rules for under-sixes — baby and child photos. And where a head covering is worn for religious or medical reasons, permitted by every authority checked, the crown is under fabric rather than hair; head coverings in passport photos covers what each authority does say.

How the tool measures it

Our photo checker finds the chin and the top of the head, converts both to millimetres using the physical height of the format you picked, and shows the result against the range that authority publishes, alongside the eye line where there is one. It is the arithmetic above at pixel precision, on any of 82 official formats — including the US, UK and Schengen visa frames. Where the authority publishes no head height, it says so instead of inventing a range to tick.

It crops, measures and checks. It does not retouch your face or replace your background. None of this is a promise of acceptance; only the issuing office decides that. What a measured head height removes is the guesswork, before somebody else does the measuring.

All of it happens in the browser tab, so you can measure the same photo twenty times without uploading it anywhere or being counted. The iOS app does the same job on a phone; it is free to download and gives one free export before asking for Pro, so for repeated retakes the website is the one to use.