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How to compress a PDF on iPhone

iOS has no built-in way to do most PDF editing — the Files app can preview and rename PDFs, and Books can read them, but combining, splitting or editing pages means either paying for an app or handing your document to a website that uploads it. A browser tool avoids both: nothing to install from the App Store, and nothing uploaded off your phone.

Hitting an attachment or upload limit is the most common reason people go looking for a PDF tool at all — the portal rejects a 12 MB file and you need it under 5 MB right now.

Open Compress PDF →

Step by step on iPhone

  1. 1Open the Compress PDF tool and upload your PDF.
  2. 2Choose a level: Light keeps text selectable, Balanced suits most documents, Strong makes scans as small as possible.
  3. 3Click “Compress PDF” and download the smaller file — you'll see the before and after sizes.

When you tap to add a file, iOS opens a picker with Photo Library, Take Photo or Video, and Choose File. Pick Choose File to reach PDFs stored in Files, iCloud Drive, Google Drive or Dropbox if you have those apps installed.

Where the finished file is saved on iPhone

Safari saves downloads to the Downloads folder inside the Files app (On My iPhone → Downloads by default). Tap the download arrow in Safari's address bar to jump straight to the finished file, then use the share sheet to move it to iCloud Drive, Mail or any other app.

What iPhone can’t do on its own

iOS can show you a PDF and let you scribble on it with Markup, but it can't merge two documents, pull out a page range, or edit existing text. Those are exactly the gaps a browser tool fills without an install.

FAQ

Do I need to install an app to do this on iPhone?
No. Everything runs in Safari or Chrome on your phone — there's nothing to download from the App Store, no account, and no subscription.
Where does the finished PDF go on my iPhone?
Into the Files app, under Downloads. Tap the download icon in Safari's address bar to open it immediately, then share it to Mail, Drive or anywhere else from there.
How much smaller will my PDF get?
It depends entirely on what's inside. Scanned documents and photo-heavy files often shrink by 70–90%. A PDF that's mostly text may only shrink a little, because there wasn't much to remove in the first place — we'll show you the real before and after numbers rather than a vague promise.
Will compressing ruin the quality?
Light is lossless — nothing is degraded at all. Balanced re-encodes pages as images at a quality that still looks clean on screen and in normal printing. Strong prioritises the smallest possible file, so fine detail softens; it's meant for scans you need to read rather than reproduce.
Why is my text no longer selectable after compressing?
Balanced and Strong work by turning each page into an image, which is what makes big files shrink dramatically — but images have no text layer. If you need to search or copy text afterwards, use the Light level, which keeps the document's text intact.
My file didn't get smaller — why?
Some PDFs are already fully optimised, and squeezing them further would actually make them bigger. When that happens we hand back your original file untouched instead of a larger “compressed” version. Trying a stronger level usually helps.
Is there a file size limit?
No fixed limit. Compression runs on your own device, so the practical ceiling is your browser's memory — everyday documents up to around 100 MB work comfortably.
Is pdfcdf free to use?
Yes. Every tool on pdfcdf is completely free, with no account, no watermarks, and no limits on how many files you process.
Are my files safe? Do they get uploaded?
Your files never leave your device. Every tool runs entirely in your browser, so your documents are processed locally and are never uploaded to a server or seen by anyone.
Do I need to create an account or sign up?
No. pdfcdf works instantly with no sign-up, no email, and no software to install — just open the tool and go.
Does it work on mobile phones and tablets?
Yes. pdfcdf runs in any modern browser on phones, tablets, Mac, Windows and Linux — nothing to download.

Ready to compress a PDF on your iPhone?

Open Compress PDF →

Same tool, other devices

Compress a PDF on AndroidCompress a PDF on MacCompress a PDF on WindowsCompress a PDF on ChromebookCompress a PDF on iPad

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