How to Reduce PDF File Size: 5 Methods That Actually Work

You've finished a report, a contract, or a presentation –and the PDF is 25 MB. Email has a 25 MB attachment limit. Your client can't download it on mobile. Sound familiar?

Here are five methods to reduce PDF file size, ordered from quickest to most thorough. All of them work entirely in your browser –no software to install, no file uploads.

Why Are PDFs So Large?

PDF files grow large for several reasons:

• High-resolution images embedded in the document (the most common culprit)
• Embedded fonts –fonts can be 1–5 MB each when fully embedded
• Hidden layers from design tools like InDesign or Illustrator
• Metadata and document history (revision history, comments, etc.)
• Redundant pages that don't need to be in the final document

Method 1: Use the PDF Compressor

The quickest method. FileCraft's PDF compressor re-saves your PDF using pdf-lib, which removes redundant structures and re-encodes the file more efficiently.

Best for: PDFs that have grown large from multiple edits or exports. Text-only PDFs and PDFs with vector graphics respond well to this method.

Limitation: If your PDF is large because of high-resolution images, the reduction will be modest. For image-heavy PDFs, use Method 3.

Typical reduction: 10–30% for text-heavy PDFs.

Method 2: Remove Unnecessary Pages

A 50-page document with 10 pages that don't need to be shared? Cut them out. Delete PDF pages lets you click to select which pages to remove, then downloads the trimmed result.

Best for: Reports with appendices, presentations with speaker notes, or any document with a cover page you don't need to share.

Tip: Use Extract PDF Pages instead if you want to pull out specific pages rather than removing them –for example, extracting just the summary section from a long report.

Method 3: Compress Images Inside the PDF

If your PDF contains photos, screenshots, or high-resolution graphics, those images are likely the main contributor to file size. The workflow:

1. Convert the PDF pages to images using PDF to Image (choose 150 DPI –enough for screen viewing, much smaller than 300 DPI)
2. Compress the images using Image Compressor or Batch Image Compression
3. Reassemble into a PDF using Image to PDF

Typical reduction: 50–80% for image-heavy PDFs. A 20 MB scanned document can often become 3–5 MB with no perceptible loss of quality.

Trade-off: This process rasterises the whole document, so text will no longer be selectable or searchable. Only use this for documents where that's acceptable.

Method 4: Split and Share Only What's Needed

Instead of compressing the whole document, consider whether your recipient actually needs all of it. Split PDF lets you extract a page range into a new file.

Example: A 50-page contract where the client only needs to review pages 3–7. Extract those pages, send a 1 MB file instead of a 15 MB one.

Best for: Sharing specific sections of large reference documents, internal reports, or anything with a clear “what they actually need” subset.

Method 5: Use the Right Export Settings from the Start

Prevention is better than compression. If you control how the PDF is generated:

• From Microsoft Word: File → Save As → PDF. Click “Options” and choose “Minimum size (publishing online)” rather than “Standard”.
• From Google Docs: File → Download → PDF Document. This uses compressed images by default.
• From Adobe InDesign/Illustrator: Export → PDF → choose “Smallest File Size” preset. Disable “Preserve Illustrator Editing Capabilities”.
• From macOS Print dialog: Print → PDF → Use the “Reduce File Size” Quartz filter.

Choosing the Right Method

Quick Tips

• Always keep the original. Compression is often irreversible, especially Method 3. Keep your original high-quality PDF before compressing.
• Target the right size for your use case. For email: under 10 MB. For web download: under 5 MB is ideal. For printing: keep the original.
• Check the result before sending. Open the compressed PDF and scan a few pages to make sure the quality is acceptable for your use case.