How to Scan Documents with Your Phone into a PDF Under a Size Limit

Sooner or later, some form asks you to "upload your documents as a single PDF, maximum 2 MB". It might be a job application, a university admission, a visa, a rental or an insurance claim. You don't need a scanner for this. A phone camera is fine, as long as you take a bit of care with the photos and then get the file under the limit. Here's how to do both.

Before you start: read the upload rules

Look for three things on the form, because they decide everything else:

• The file size limit, for example 500 KB, 1 MB or 2 MB. Sometimes it applies to each file, sometimes to everything you upload together.
• Whether they want one PDF or separate files. "Combine all pages into one document" is common. So is one PDF per document type (ID, certificates, payslips).
• Any page size or quality rules. Some ask for A4, or for scans that are "clear and legible", which in practice means someone has to be able to read the small print.

Taking a good photo of a document

Most unreadable scans come down to light and angle, not the phone. A few minutes of setup makes a big difference.

Light

• Work near a window in daylight, or in a well-lit room. Dim light makes the phone blur the image or add grain.
• Watch your own shadow. Standing between the light and the page is the most common mistake. Move so the light comes from the side or from in front of you.
• Avoid the flash on glossy paper or laminated cards. It leaves a bright white patch that hides whatever is under it.

Position

• Put the page on a plain, dark surface such as a table or a sheet of dark card. The contrast makes the edges obvious and the page easier to crop.
• Hold the phone flat and directly above the page. Shooting at an angle turns the rectangle into a trapezoid and makes the far side harder to read.
• Fill the frame with the page, leaving a small border around it.
• Flatten folded pages. Put something heavy on the corners if they curl.

Check it straight away

Zoom in on the smallest text on the page before you move on. If you can't read it on your phone, the person checking your application won't be able to either. Retake it now; it's much easier than finding the document again later.

What about the scanner apps built into phones?

Many phones already have a document scanner. On an iPhone, the Notes app can scan documents and the Files app can too. On Android, the Google Drive app has a scan button. They straighten pages automatically and can save straight to PDF, which is great.

Where they fall short is file size. They usually don't let you say "keep it under 1 MB", and a few pages scanned at full quality can easily go over the limit. In that case, save the pages as images instead, or take normal photos, and build the PDF with a size limit as described below.

Turning the photos into one PDF under the limit

1. Open the Image to PDF tool and add all the photos. Each one becomes a page.
2. Check the order and use the arrows to fix it. Rotate any page that came out sideways. Phones usually get this right, but not always with documents shot from above.
3. Choose A4 or US Letter, depending on where you are, with a small margin.
4. Type the form's limit into Max file size, for example 2 MB. If the limit covers everything you upload together, divide it between the files and leave a little room.
5. Create the PDF, download it and open it. Zoom in on the small print once more before you upload.

If the form wants a separate PDF for each document, say one for your ID and one for your certificates, choose Choose how many under "PDFs to create", type the number, and drag each photo into the right PDF box. Give each one a clear name before you download.

The tool keeps quality as high as the limit allows. It lowers the image quality first and only reduces the resolution if that isn't enough, and it won't go below the point where text stops being readable. Your documents stay on your device the whole time; nothing gets uploaded to us.

How much space does a page need?

It depends on the page. A typed letter on white paper compresses well; a colorful certificate with a patterned background or a photo ID needs more. We tested it with phone photos of typed A4 pages (about 3 MB each, straight from the camera), and this is how many still came out readable:

At the top end of each range, normal-sized text is still clear but small print gets soft, so treat these as a ceiling rather than a target. Colorful, busy or shadowy pages need more room. If the tool says it can't reach your limit while keeping pages readable, split the document into two PDFs or drop pages the form didn't ask for.

A few more tips

• Give the file a clear name. "Passport-Ayesha-Khan.pdf" is far more helpful to whoever processes your application than "IMG_4821.pdf".
• Scan both sides of ID cards and anything printed on the back, unless the form says otherwise.
• Don't edit the content. Cropping and straightening are fine. Changing anything on the document itself is not.
• Need a single image instead of a PDF? Some forms want a photo or signature as a JPG under, say, 50 KB. The image compressor does that.