How to Turn Photos Into One PDF on Your Phone

Short answer: pick the photos, put them in the right order, choose a page size (A4 or US Letter) and orientation, and export them as one PDF. On your phone it takes a few taps, and it turns a pile of separate pictures into a single document that opens the same way for everyone who receives it.

Why send one PDF instead of several photos?

Photos work for a single receipt. They become a problem as soon as a document has more than one page:

• The order gets lost. Three attachments called IMG_4471, IMG_4472 and IMG_4473 rarely arrive in a reliable order, and the person reading them has to guess which page comes first.
• They open at different sizes. A photo is shown at whatever size the receiving phone or email app decides, so a form can look fine on your screen and tiny on theirs.
• They print badly. Photos have no page size, so a printer has to guess, and the usual result is a cropped edge or a page scaled down to a corner.

A PDF fixes all three: one file, a fixed page order and a defined page size that prints the way it looks.

Before you start: A4 or US Letter?

The page size is easy to get wrong. A4 measures 210 × 297 mm, and US Letter measures 8.5 × 11 inches (215.9 × 279.4 mm), according to Wikipedia's article on US Letter paper. US Letter is used mainly in the United States, Canada and the Philippines, and in parts of Latin America. Most other countries use A4.

The two sizes are close but not the same. A4 is narrower and longer than US Letter. A page made for one and printed on the other usually loses a few millimetres at an edge or gets scaled down. If the PDF is going to a school, an employer or a government office, use the size that country prints on. Outside North America, A4 is the safer choice when in doubt.

Step by step: photos to one PDF with ScanMint AI

ScanMint AI has a dedicated Image to PDF tool. It works like this:

1. Select your photos. Open Image to PDF and pick one image or a whole set from your gallery.
2. Put them in order. Arrange the pages in reading order. A three-page form stays a three-page form, in the right sequence.
3. Choose the page setup. Pick A4 or US Letter, portrait or landscape, and set the page margin. A small margin keeps text away from the edge, so nothing is cut off when it is printed.
4. Export the PDF. The photos are combined into a single file, which is saved in your history in the app, ready to share, sign or merge.

The conversion happens on your phone, so the photos are not uploaded to our servers, and it works without a connection. Image to PDF is a Premium tool. On the free plan you can unlock it for a session by watching one short ad instead of paying; see pricing for the details.

Common jobs this solves

• Expense claims. Photograph each receipt as you get it, then turn the week's photos into one PDF for your finance team, in date order.
• Forms you have already filled in. If you completed a paper form and took pictures of each page, one PDF keeps the pages together and in sequence.
• Notes and whiteboards. Lecture slides or a whiteboard after a meeting become one landscape document you can file or share.
• Homework and coursework. Some schools and course portals ask for a single PDF upload rather than several images.

In each case the value is the same: one file, in order, at a page size the reader can print.

Photos or a scan: which should you use?

Image to PDF is the right tool when the photos already exist: pictures of a whiteboard, screenshots, or snapshots of receipts you took earlier. When the original is still a piece of paper in front of you, scanning usually gives a cleaner result.

The difference is what happens to each page. Each photo keeps whatever angle, shadow and background you captured it with. Scan Documents straightens and crops each page before building the PDF, so a sheet photographed at a slight angle comes out square, without the surrounding table. Our guide on how to scan documents to PDF on your phone covers that route in detail.

Tips for a PDF that looks right first time

• Check every photo is the right way up before you export. A sideways page inside a PDF is more annoying to fix than a sideways photo.
• Match the orientation to the content. Use portrait for forms, letters and receipts, and landscape for wide tables, slides or a whiteboard.
• Keep a margin if the document might be printed. Many printers leave a thin unprinted border, so content placed right at the edge can be lost.
• Give the file a clear name when you share it, such as "Tenancy form – signed – Oct 2026.pdf". It will sit in someone's downloads folder next to dozens of others.
• Crop out what should not be there. A photo of a document often includes a bank card, a face or a screen in the background. Crop it before you convert, because the PDF will contain exactly what was in the picture.

After the PDF is made

A PDF built from photos is often only one step of the job. If the document needs a signature, you can add one on your phone with Signature instead of printing it. If it belongs with other files, such as a covering letter, PDF Merger combines them into one; our article on merging and organising PDFs shows how.

Phones also have built-in ways to make a PDF, usually through the share or print menu. The steps depend on your phone and its software version. They can be fine for a one-off. Check whether they let you set the paper size, orientation and margin, because those settings decide whether the PDF prints properly.

Frequently asked questions

Can I combine several photos into one PDF on my phone?

Yes. Select all the photos, arrange them in order and export them. They are combined into one PDF in the order you set.

Should I choose A4 or US Letter?

Use US Letter if the document is for the United States, Canada or the Philippines, and A4 almost everywhere else. If you do not know where it will be printed, A4 is the more common choice worldwide.

Are my photos uploaded when I convert them?

In ScanMint AI, Image to PDF runs on your phone, so the photos are not uploaded to our servers. The app also includes ads, analytics and crash reporting; see our Privacy Policy for what those collect.

Is it better to scan or to convert photos?

If the paper is in front of you, scan it: the scanner straightens and crops each page. If you only have photos, convert them with Image to PDF.