Resizing a photo to 35 × 45 mm: tools compared, and why pixels matter more than millimetres

35 × 45 mm describes a printed photo. An online portal never sees millimetres. It reads the file's pixel size, its file size and how much of the frame your face fills, and countries that all print at 35 × 45 mm ask for different files: Singapore's ICA wants 400 × 514 pixels, the UK wants at least 600 × 750, and Indian passport applications ask for 630 × 810 under 250 KB.¹²³ So the best resizing tool is the one that knows your document's pixel target. Free browser tools such as idphotosize.com and Pi7 let you type in sizes yourself. Paid processors such as Visafoto and PhotoAiD pick the size for you after you choose a country.⁴⁵⁶⁷ SpecSnap is a phone app whose document presets already carry the pixel size, face-height ratio and file-size cap, and it runs on your phone, from $0.99 per export on the US App Store.⁸⁹

35 × 45 mm is a print size. Your upload is judged in pixels.#

A millimetre only means something once the photo is printed. On screen, a photo is a grid of pixels, and how big it prints depends on how many of those pixels you squeeze into each inch (the DPI). The same 35 × 45 mm frame is 413 × 531 pixels at 300 DPI and 827 × 1063 pixels at 600 DPI.⁶ Both print at exactly 35 × 45 mm. They're very different files.

That's why "resize to 35 × 45 mm" is an incomplete instruction for an online application. One VFS Global photo sheet says it plainly: resolution "is mainly used to control printing quality."¹⁰ The portal checks the pixel grid and the file weight. DPI is a note to the printer.

Here's what four portals ask for, all for a photo that prints at or near 35 × 45 mm:

Four things jump out.

• Singapore's 400 × 514 isn't the 300 DPI number. Spread over 35 mm, 400 pixels works out to about 290 DPI.¹¹ A file made with the common "35 × 45 mm at 300 DPI" setting comes out at 413 × 531, which is a different size from the one ICA lists.
• The UK's minimum is a different shape. 600 × 750 is a 4:5 rectangle, while 35 × 45 mm is 7:9. A 7:9 crop that's 600 pixels wide is 771 pixels tall, which clears the minimum. SpecSnap's UK preset uses exactly that, 600 × 771.¹²
• India's file is bigger in pixels but capped tight in kilobytes. 630 × 810 pixels under 250 KB means real JPEG compression. The same embassy notice wants your face to cover roughly 85% of the image, a tighter crop than many other document routes; do not infer an ICA percentage from the app’s legacy crop reference.³¹¹¹³
• Some visa portals don't use 7:9 at all. The VFS sheet for Belgian visas asks for a 3:4 proportion and rejects anything over 120 KB.¹⁰

So two photos can both be "35 × 45 mm" and only one of them passes. The pixel numbers for more countries are in our visa photo pixel dimensions reference, and the byte caps are in file size limits on passport and visa upload portals.

Resizing, cropping and editing are three different jobs#

Tools blur these together. Agencies don't.

Resizing changes how many pixels the image has. It doesn't move anything inside the frame. If your head is too small in the original, it's still too small after a resize, only now at the right pixel count.

Cropping decides what's inside the frame: how big your head is and where your eyes sit. This is where most rejections start. The UK's printed spec wants a face 29 to 34 mm tall inside the 45 mm height.¹⁴ India wants about 85% of the image covered by the face.³ SpecSnap's Schengen preset targets a face height of 71 to 80% of the frame.¹³ A resizer that only scales the whole picture gets none of that right by accident. The head size ratio guide explains why the numbers differ, and apps that crop to exact pixel specs covers the crop side in depth.

Editing changes the picture itself: lighting, skin, clothes, the background. This is where the rules get strict. ICA says a photo "must not be altered or enhanced in any way", and that includes "the modification of facial features and/or the usage of photo editing software." In the same breath it allows editing software "to resize the digital photograph."¹ GOV.UK says the photo must be "unaltered by computer software."² India is more relaxed on one point: its notice says applicants without a studio photo can use paintbrush-style tools to make an uneven background uniform, preferably white, and crop to the 85% face rule.³

The practical rule is simple. Resize and crop freely. Treat anything that changes your face, your clothes or the light on you as a risk, and check your own agency's wording before you use it.

The tools compared#

Every tool below can produce a 35 × 45 mm photo. They differ in whether you or the tool picks the pixel size, where your photo gets processed, and how much they change beyond size and crop.

A few notes the table can't hold.

idphotosize.com is the strongest free option if you already know your portal's numbers. It runs in the browser on your own device, lets you set any pixel size, and can compress to a target between 20 KB and 2 MB.⁴ It also shows a photo analysis panel for open eyes, neutral expression and a straight head.⁴ What it can't do is know which numbers your portal wants. You bring those.

Pi7 lists its 35 × 45 mm preset for "India, Australia, Europe, UK, Pakistan" in one button.⁵ As the table above shows, those countries want different pixel sizes, so treat the preset as a starting frame and check the exported file's pixel size yourself. Pi7 also says "most online passport photo submission portals require an image size of 50kb."⁵ Don't rely on that. The UK uses 50 KB as a floor, not a target, and ICA allows up to 8 MB.²¹ The outfit changer is the feature to skip for any agency that bans altered photos.

Visafoto does the most work for you. Pick a country and document and it adjusts the size, background colour, head position and format, then gives you a digital file and a 4 × 6 inch print template.⁶ You can preview the result before paying.¹⁶ If a photo is rejected for technical reasons, Visafoto says it will remake it free or refund you.⁶ The catch is the enhancement step. Lighting and "clothing extension" changes are the kind of edits ICA and GOV.UK rule out, so if you apply in Singapore or the UK, read your agency's wording first.¹²

PhotoAiD is the pick if you want a person to look at your photo. It offers 24/7 expert verification and says that if authorities reject your photo, "you'll get a full refund plus an extra 100% of the price."⁷ You upload the photo to its service, and the price only appears at checkout.

A desktop editor works if you're comfortable judging head size by eye. Visafoto's own instructions are the standard recipe: crop to a 35:45 ratio with the face centred and shoulders in frame, set the image size to 3.5 × 4.5 cm, and use at least 300 DPI.⁶ That gets the print right. For an upload, set the pixel size your portal lists rather than trusting the DPI to produce it.

For Singapore Passport / IC and online Visa, SpecSnap now provides original-photo guidance without edited generation, previews, payment or application export. ICA permits resizing but requires an original, unaltered photo; the original-preserving checker is not yet implemented.

Which tool fits which job#

You know your portal's exact pixel and file-size numbers and want it free. Use idphotosize.com, set the pixel size by hand, and check the face proportion against your country's spec.

You only need prints, for example a Schengen visa on paper. Any tool that lays 35 × 45 mm photos on a 4 × 6 inch sheet at 300 DPI or more will do. Print at 100% scale, not "fit to page". The 4 × 6 printing guide covers the settings, and photo apps for a European passport covers the shared 35 × 45 mm biometric spec.

You want someone to check it, and you're fine uploading your photo. PhotoAiD's expert review and refund-plus-100% guarantee are the reason to pay. Visafoto also sets everything for you, but read its enhancement step against your agency's rules.

You apply for more than one country, or you don't want your face on anyone's server. SpecSnap picks the right pixel target per document and does the work on your phone. The wider field is compared in our best passport photo apps for 2026.

A 60-second check after any resize#

Whatever tool you use, open the finished file and check these before you upload:

1. Pixel size. Your computer or phone shows it in the file info. It should match the number your portal lists, which is never just "35 × 45 mm".
2. Shape. 7:9 for most 35 × 45 mm specs, but check: some portals want 3:4.¹⁰
3. File size. Inside both the floor and the ceiling. The UK rejects under 50 KB; India rejects over 250 KB.²³
4. Format. JPEG is the safe default. VFS's Belgian sheet accepts nothing else.¹⁰
5. Face size. Your head should fill the share of the frame your spec asks for, not whatever the original happened to have.
6. Nothing altered. No skin smoothing, relighting or swapped clothes, unless your agency explicitly allows it.

Steps 1 to 4 are numbers a tool can get right. SpecSnap's presets set the pixel size, shape and file size for you, and its validator measures face height and eye line before export.⁸¹¹ Steps 5 and 6 are where a free resizer leaves you on your own. For a full upload checklist, see where to get a digital passport photo that's ready to upload.

Frequently asked questions#

How many pixels is a 35 × 45 mm photo? It depends on the DPI. At 300 DPI it's 413 × 531 pixels, and at 600 DPI it's 827 × 1063.⁶ For an online application, ignore the DPI and use the pixel size your portal lists, such as 400 × 514 for Singapore's ICA.¹

Is 35 × 45 mm the same as 3.5 × 4.5 cm? Yes. It's also about 1.38 × 1.77 inches. It is 35 mm wide and 45 mm tall.⁶

Am I allowed to resize my own passport photo? In Singapore, yes: ICA explicitly allows editing software "to resize the digital photograph", while banning any other alteration.¹ The UK says the photo must be "unaltered by computer software", so stick to resizing and cropping and nothing that changes the image itself.²

Why did my resized photo get rejected when the size was right? Usually because resizing kept the original composition. If your head was too small or off-centre before, it still is. Crop to your spec's face-height ratio, then resize.

Sources#