How to Reduce PDF Size on iPhone — 3 Methods

The iPhone PDF Problem

iPhones are great at creating PDFs — you can scan documents with the Notes app, save web pages as PDF, or export from Pages. But the resulting files are often larger than expected, especially scanned documents that embed high-resolution camera images. Sharing a 12 MB scan via iMessage or email hits size limits fast.

Method 1: Browser-Based Compression (Recommended)

The simplest approach that works on any iPhone without installing an app. Open Safari and go to FileKit PDF Compressor:

1. Tap the upload area and select your PDF from Files or Photos
2. Choose a compression level — Balanced works for most documents
3. Tap Download to save the compressed PDF to your Files app

Everything runs locally in Safari — your document never leaves your iPhone. This is especially important for bank statements, medical records, or ID scans.

Method 2: Use the Shortcuts App

iOS Shortcuts can automate PDF compression using the built-in “Make PDF” action. Create a shortcut that:

1. Accepts a PDF file as input
2. Converts each page to an image at reduced quality
3. Combines the images back into a new PDF

This approach works offline but requires some setup and reduces quality more aggressively than browser-based tools.

Method 3: Re-Scan at Lower Resolution

If the PDF was created by scanning in the Notes app, the easiest fix is re-scanning. Open the document scanner and look for quality settings — choosing a lower quality or grayscale option produces significantly smaller files.

Tips for Smaller PDFs on iPhone

• Scan in grayscale when color is not needed — this can cut file size by 50% or more
• Crop before saving — the Notes scanner lets you adjust the crop area. Tighter crops mean fewer pixels
• Use fewer pages — only scan the pages you actually need to send
• Share as a link — if the file is still too large, upload to iCloud Drive and share a link instead of the file itself
• Convert HEIC photos first — if you are creating a PDF from iPhone photos, consider converting HEIC to JPG to control the image quality before combining into a PDF

Size Expectations