How to Make a PDF Smaller on iPhone
Last updated
iPhones produce gorgeous, enormous files. The same high-resolution camera and scanner that make your documents look sharp also make the PDFs heavy — a few scanned pages can sail past an email limit before you've added anything else. So "make this PDF smaller on my iPhone" is a very common, very specific need.
This guide covers two reliable routes that both work on iPhone. The first is the free Compress PDF tool in Safari, which runs on your device with nothing uploaded. The second is the PDF Editor app, which compresses offline and handles password-protected files the browser can't.
Either way, the goal is the same: a file small enough to email or upload that still reads cleanly — without sending your document off to someone else's server to get there.
Step by step
- 1
Find the PDF in Files
Locate the document in the Files app or wherever it lives — a scan you made, an attachment you saved, a converted photo bundle.
- 2
Open the Compress PDF tool in Safari
Go to the Compress PDF tool. It runs in the browser on your iPhone and processes the file on the device — nothing is uploaded.
- 3
Add the PDF and choose a level
Tap to select the file, then pick a level. Recommended suits most cases; choose Strong only if you need it smaller still.
- 4
Compress and check the size
Run it and read the before-and-after size. iPhone scans typically drop a lot in one pass because they're image-heavy.
- 5
Save it back to Files or share it
Use the share icon to save the smaller PDF to Files or send it straight on. Keep the original until you've confirmed the result reads well.
- 6
For protected files, use the app
The browser can't compress password-protected PDFs. The PDF Editor app handles those offline, and is faster for files you compress often.
Tips
- iPhone scans are big because they're high-resolution images. That's also why they compress so well — the savings are largest on exactly these files.
- Shooting documents in "Most Compatible" format (Settings → Camera → Formats) produces JPGs that are easier to compress and share than HEIC.
- Compression rasterises pages, so the smaller copy won't have selectable text. Keep the original if you need to search or copy from it.
- Browser memory on a phone is more limited than on a laptop. For very large PDFs, the PDF Editor app is the more reliable route.
- Always save the compressed file under a new name so your sharp original stays intact on the device.
Try it on your phone
This is a phone-first task, and the PDF Editor app is built for it: compress offline, no upload, support for protected files, and a direct hand-off to Mail, Messages or the share sheet. For documents you shrink regularly, it's quicker than the browser each time.
