How to Compress a PDF on iPhone

How do I compress a PDF on my iPhone?

Open Safari and go to Compress PDF on this site. Tap Choose PDF files and pick the PDF from your files. Choose Balanced, or Strong for a smaller file, then tap Compress PDF. When it finishes, the page shows the old and new sizes; tap Download to save the smaller copy. Nothing is installed and nothing is uploaded.

1. Open Safari and go to Compress PDF.
2. Tap Choose PDF files and pick the PDF from your files.
3. Choose Balanced, Strong, or Target size and type a limit.
4. Tap Compress PDF, check the new size, then tap Download.

Which level should I pick on a phone?

Pick Balanced for most sharing: in our test it cut a 7.79 MB phone scan to 559 KB, with the text still clear. Pick Strong to meet a strict upload limit: the same scan came to 313 KB. In our separate compression study, OCR still read 100% of the words in a scanned letter at Strong.

This site's production build in Chrome 152 set to a 375 x 812 phone screen on a laptop (i5-8350U), not on a real iPhone, 2026-10-12. A real iPhone will take a different time. The full level-by-level results are in our PDF compression test.

Where does the compressed PDF go?

When you tap Download, Safari saves the smaller PDF to your phone, where you can find it in the Files app, usually in Downloads. From there you can attach it to an email, upload it to a form, or share it to another app. The original file is not changed, so you keep both copies until you delete one.

The download takes the original name with "compressed" added, so the two files are easy to tell apart. Apple says Safari saves downloads to the Downloads folder in iCloud Drive unless you choose another place in Settings, Apps, Safari, under Downloads. The Downloads button in Safari also lists the files you just saved.

Is it safe to compress a PDF on my phone?

Yes, with this tool the PDF stays on your iPhone. The page downloads its compression code once, then works on the file inside Safari; no copy is sent to a server. You can check: load the page, turn on Airplane Mode, and compress a file. It still works, because nothing needs to travel over the internet.

Our guide Is It Safe to Upload a PDF Online? shows the network test we ran on this tool and explains how to check any site.

What if the PDF is too big for my phone?

Phones have less memory than laptops, so very large PDFs, such as long scans of hundreds of megabytes, can fail on a phone. On a phone the tool accepts up to about 120 MB at once and says so instead of letting Safari crash. Split it into parts, or compress it on a computer.

For a size limit you must meet, see PDF Too Large to Upload?; for long documents, Split PDF also works on an iPhone.