How to Compress a PDF on iPhone (Shrink Files for Email)

"Attachment too large." Scanned documents are usually image-heavy, so a ten-page scan can easily hit 30–50 MB — past the limit for most email providers and messaging apps. Uploading your documents to a random compress-PDF website is the common workaround, and a bad one: you're handing your files to an unknown server. Here's how to shrink PDFs directly on your iPhone instead.

Compress a PDF in Scanniq

1. Open Scanniq and tap Tools
2. Select Compress
3. Pick the PDF — from your scanned documents or import from Files
4. Choose a quality level (see below) and preview the new file size
5. Tap Compress, then share or save the smaller file

Everything runs on-device. Your document never leaves your phone.

Which quality level should you pick?

• High quality: barely visible difference, typically 30–50% smaller. Use for contracts and anything that will be printed
• Balanced: the sweet spot for email — usually 60–80% smaller with text still crisp
• Small size: maximum shrink for quick sharing in chat apps; fine text may soften slightly

Prevention beats compression

If your scans are routinely huge, two habits keep them small from the start: scan in black & white or grayscale when color adds nothing (a receipt doesn't need color), and let the scanner's auto-crop remove the table around your page — background pixels are wasted kilobytes.

Common combos

• Merged file too big? Merge your PDFs first, then compress the combined file once
• Sending photos as documents? Convert images to PDF and compress in the same flow
• Application portals with strict limits (visa, university, government forms) usually cap uploads at 2–5 MB — the Small size preset gets a typical scan under that