Trying to email a PDF from your iPhone but it is too large? Or maybe a messaging app is refusing to send it? Compressing a PDF on your iPhone is straightforward once you know the right approach. Here are all the free methods that actually work.
Method 1: Use the Files App
The Files app does not have a built-in compressor, but you can use it with third-party services:
- Open Files and locate your PDF
- Long-press the file and tap Share
- Choose a compression app from the share sheet
- Save the compressed version back to Files
Method 2: Use Safari with an Online Compressor
The fastest approach for most people:
- Open Safari on your iPhone
- Go to a free PDF compressor like iLovePDF.com or SmallPDF.com
- Tap Select PDF and choose your file
- Pick a compression level (basic compression is usually enough)
- Download the compressed file
Most online compressors reduce file size by 40-75% without visible quality loss. For documents with mostly text, the savings are even bigger.
Method 3: Print to PDF Trick
A clever iOS trick that sometimes reduces file size:
- Open the PDF in any viewer
- Tap Share then Print
- Pinch outward on the print preview to expand it
- Tap Share again and save the new PDF
This re-renders the PDF, which strips unnecessary data and sometimes produces a smaller file.
Method 4: Dedicated Free Apps
These apps are designed specifically for PDF compression on iOS:
- Adobe Acrobat Reader — Free with basic compression. Open the PDF, tap the three dots, and look for "Compress PDF."
- PDF Expert (by Readdle) — Excellent compression quality, free tier available
- Microsoft Lens — If your PDF is a scanned document, re-scanning at lower resolution can dramatically reduce size
How Much Can You Compress?
Realistic compression results on iPhone:
- Text-heavy PDFs: 60-80% reduction (a 10MB file becomes 2-4MB)
- Mixed text and images: 40-60% reduction
- Image-heavy PDFs: 30-50% reduction depending on image resolution
- Scanned documents: 50-70% reduction
Compressing for Specific Apps
For Email (Gmail, Outlook)
Most email providers have a 25MB attachment limit. Compress to under 20MB to be safe. If your PDF is still too large after compression, split it into smaller parts.
For iMessage
iMessage handles files reasonably well, but large PDFs may take forever to send. Compress to under 5MB for the best experience.
For WhatsApp
WhatsApp has a 100MB document limit, but it also compresses files on its own. Still, pre-compressing gives you more control over quality.
When Compression Is Not Enough
If your PDF is massive (100MB+) and compression is not cutting it:
- Extract only the pages you need — No point sending a 50-page document when you only need page 3
- Convert images to lower resolution before creating the PDF
- Use a cloud link — Upload to iCloud Drive, Google Drive, or Dropbox and share the link instead