What the Passport Photo Size Checker does
This checker measures a passport or visa photo against the published size rules for the document you choose: the frame shape, the head height from chin to crown in millimetres, the pixel size for digital applications and the print resolution. It then suggests a correctly sized crop and can lay the result out on a 6 x 4 inch print sheet.
You mark the top of the head and the chin yourself; everything else is arithmetic against rules taken from the official pages, which are listed with the date they were checked. There is no face detection and no biometric processing, and the photo is measured in your browser without being uploaded.
How to use it
- Choose the document rules: US passport (2 x 2 in), UK passport (35 x 45 mm), Canadian passport (50 x 70 mm) or the general ICAO-style 35 x 45 mm used by many countries.
- Load your photo. Take it against a plain light wall, facing the camera, with space above the head and the shoulders in view.
- Click the very top of the head, including hair, then the bottom of the chin. You can fine-tune both marks in the number boxes.
- Read the checks. If the frame or head height is wrong and there is enough space around you, use the suggested crop, then download the photo or a print sheet to print at 100% with no scaling.
Reading the results
Head height is the distance from chin to crown as it will appear on the printed photo. It is worked out as the marked head in pixels divided by the photo height in pixels, times the document height in millimetres - so it only makes sense once the frame has the right shape.
Print resolution is the photo width in pixels divided by the printed width in inches. 300 pixels per inch is the usual target for sharp photo prints; it is a printing convention, not a passport rule.
The background check samples the two top corners for brightness and evenness. It is an A2Z heuristic that can flag a dark or shadowed wall; it cannot tell whether an office will accept the colour.
Worked example: a phone photo cropped for a UK passport
A phone photo is 3000 x 4000 pixels. The top of the hair is at 900 px and the chin at 1800 px, so the head is 900 px tall. As it stands, the frame is 3:4 (0.750) instead of 35:45 (0.778), and the head would print at 900 / 4000 x 45 = 10.1 mm - far below the UK range of 29 to 34 mm.
The suggested crop aims for the middle of the range, 31.5 mm. The crop height is 900 x 45 / 31.5 = 1,285.7 px and the width 1,285.7 x 35 / 45 = 1,000 px. The head then prints at exactly 31.5 mm, and the photo prints at 1,000 / (35 / 25.4) = about 726 pixels per inch, well above 300.
On a 6 x 4 inch (152.4 x 101.6 mm) print with 2 mm gaps, 4 columns and 2 rows fit: floor(154.4 / 37) = 4 and floor(103.6 / 47) = 2, so the sheet holds 8 photos.
Formulas and scoring rules
- Head height on the print
head mm = (chin px - crown px) / photo height px x document height mm- Frame shape
width px / height px must be within 1% of width mm / height mm- Print resolution
ppi = width px / (width mm / 25.4)- Suggested crop
crop height = head px x document height mm / ((min head + max head) / 2); crop width = crop height x width mm / height mm45% of the spare height goes above the head - an A2Z convention.- Photos per sheet
floor((sheet + gap) / (photo + gap)) in each direction; the better orientation is used
Limitations: what the result does not prove
- Only measurable rules are checked. Expression, open eyes, glasses, shadows on the face, lighting, focus, likeness and how recent the photo is are decided by the issuing office.
- The result depends on where you place the marks. Mark the top of the hair, not the forehead, and the bottom of the chin, not the jaw line.
- Rules change and differ between passports, visas and online applications. Re-read the official page for your application before printing, and follow it where it differs from the preset.
- The page never enlarges a small photo to meet a pixel minimum or paints in missing background. If the crop runs off the edge, retake the photo.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- ICAO Doc 9303 - Machine Readable Travel Documents (photo requirements, Part 3) - checked 19 Sep 2026
- U.S. Department of State - Passport photos
- GOV.UK - Photos for passports: photo requirements
- Government of Canada - Passport photos
Frequently asked questions
What size is a US passport photo in pixels?
The US Department of State asks for a square digital photo between 600 x 600 and 1200 x 1200 pixels, which prints at 2 x 2 inches. The head, chin to top of hair, must measure 1 to 1 3/8 inches (25.4 to 34.9 mm) on that print.
How big should my head be in a UK passport photo?
GOV.UK asks for a printed photo 45 mm high and 35 mm wide with the head, chin to crown, between 29 and 34 mm. Digital photos for online applications must be at least 600 pixels wide and 750 pixels tall.
Does this tool use face recognition?
No. You mark the top of the head and the chin yourself, and the page measures the distance between your marks. No face detection or biometric template is created, and the image is not sent anywhere.
Why does the checker say my photo is the wrong shape?
A phone photo is usually 3:4 or 9:16, while a UK photo is 35:45 and a US photo is square. Head height only makes sense once the frame has the document's shape, so use the suggested crop first.
How do I print passport photos at the right size at home or in a shop?
Download the 6 x 4 inch print sheet. It is laid out at 300 pixels per inch, so print it at 100% or actual size on 6 x 4 photo paper, with no fit-to-page or borderless enlargement, then cut along the grey lines.
Will a photo that passes these checks be accepted?
Not necessarily. Passing means the measurable size rules are met. The issuing office also checks expression, lighting, background, glasses and likeness, and it makes the final decision.
Last reviewed by the A2Z.Tools team against the sources listed above.
