Why Are My PDFs So Large?

If you've ever wondered why a simple document turns into a 50MB PDF, here are the most common causes.

Top Reasons

1. High-Resolution Images

The #1 cause. A single high-res photo can be 5-10MB. Multiple photos add up fast.

2. Scanned Documents

Each scanned page is stored as a full image at 300 DPI. A 10-page scan can be 20-50MB.

3. Embedded Fonts

PDFs embed fonts for consistent display. Each font family adds 100KB-1MB.

4. Layers and Editing History

Design tool PDFs may contain hidden layers and unused objects.

5. Metadata

Hidden metadata, form data, and JavaScript increase size.

How to Fix It

Use a PDF compressor to strip unnecessary data and optimize images. Typical reduction: 30-80%.

Prevention Tips

• Export images at web resolution (72-150 DPI) for screen-only PDFs
• Remove unused layers before exporting
• Subset fonts instead of embedding full font families
• Use PDF/A format for archival (removes unnecessary features)