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How to Compress a PDF on iPhone

Most large PDFs are large because of the photos or scans inside them. Here’s how to shrink those on iPhone with the built-in Preview app, when PDFee is quicker, and what you give up in return.

PDFee teamUpdated September 27, 2026 · 5 min readTestediPhone 14 Pro · iOS 26.6.2 · PDFee 1.6
On this page
  1. Quick answer
  2. What makes it large
  3. Which method?
  4. Method 1 · Preview
  5. Method 2 · PDFee
  6. Check the result
  7. Save and share
  8. Questions

Quick answer

Open the PDF in the Preview app, tap the file name at the top and choose Export. Pick PDF, turn on Optimize Images for Screen and Save Images as JPEG, then save the copy.

Want a smaller copy in two taps, with the new size shown first? In PDFee:
  1. 1Tap Compress
  2. 2Choose the PDF
  3. 3Pick Email-ready

Check what makes your PDF large

A PDF’s size mostly comes from what’s inside it. Knowing which kind you have tells you how much compressing can help.

PhotosPDFs made from photos are often several MB per page. Compresses well.
ScansScanned pages are images too. Compresses well, but check small print afterwards.
Text documentsExported from Word or Pages, mostly text. Already small: compressing helps little.

Which method should you use?

You want to…PreviewFiles › CompressPDFee
Make the PDF itself smaller
See the new size before sharing
Keeps text selectableNo, pages become images
Works on a copy
ResultPDF.zip archivePDF
Method 1 · Built in

Try the native Preview compression options

iPhone has a Preview app for PDFs and images (iOS 26 and later). Its export options can shrink the images inside a PDF.

  1. Preview › open PDF
    Step 1Open the Preview app and open the PDF.
  2. Export menu
    Step 2Tap the file name at the top, then Export.
  3. PDF export options
    Step 3Choose PDF as the format (if you don’t see it, tap the options button first) and turn on Optimize Images for Screen and Save Images as JPEG. Then tap the checkmark and choose where to save the copy; the original stays as it was.
Method 2 · App

Compress a photo or scanned PDF with PDFee

PDFee shows the current size, lets you pick how small to go, and shows the new size before you send it. It works on a copy on your iPhone; nothing is uploaded.

  1. Open PDFee and tap Compress

    It’s one of the four tiles on the home screen.

    Step 1: Open PDFee and tap Compress

  2. Tap Choose PDF

    Pick the PDF in Files. PDFee shows its page count and Current size.

    Step 2: Tap Choose PDF

  3. Pick Email-ready or Small

    Email-ready keeps pages sharp enough to read and print. Small goes further, for strict size limits.

    Step 3: Pick Email-ready or Small

  4. Tap Compress, then share or save

    The New size appears next to the current size and the share sheet opens. The copy is also kept under Recent in PDFee. If the new size isn’t smaller, keep your original.

    Step 4: Tap Compress, then share or save
Free and Pro for this taskChecked in PDFee 1.6
FreeCompressing is included, with no watermark.
ProNothing extra for compressing. Pro removes the page and merge limits elsewhere in the app.
Try PDFee on your iPhone

Check the smaller PDF before you send it

Zoom in on small printCheck dates, amounts and signatures at full zoom before sending.
Try selecting textIf you need to copy or search text later, keep the original too.
Check the limitMany email services cap attachments at around 20–25 MB in total.

Save a copy and share the smaller PDF

Questions

How do I decrease the MB of a PDF?

Shrink the images inside it. In Preview, export the PDF with Optimize Images for Screen and Save Images as JPEG turned on. In PDFee, compress it with Email-ready or Small. PDFs that are mostly text are already small and barely change.

How can I compress a PDF on my phone?

On iPhone, use the Preview app’s export options, or a PDF app such as PDFee. Both work on the iPhone itself, without uploading the file.

How do I compress a file on my iPhone?

The Compress option in the Files app makes a .zip archive. That helps for sending many files at once, but it barely shrinks a PDF. To make the PDF itself smaller, use one of the methods above.

Will compressing make my PDF blurry?

It can. Compression lowers image resolution. Try the lighter setting first (Email-ready in PDFee), zoom in on small text, and only go smaller if you need to.

Written and tested by the PDFee teamTested on iPhone 14 Pro, iOS 26.6.2, PDFee 1.6, September 26, 2026. Screenshots come from that test and from Apple’s iOS Simulator, with test files in place of personal ones. We update this guide when iOS or the app changes.