How to Compress PDF Files

PDFs balloon in size when they contain high-resolution scans, embedded fonts, or complex graphics. Email attachment limits (usually 25 MB) and slow upload speeds make sharing painful.

Most bloat comes from images embedded at print resolution (300 DPI or higher) even when the document is only viewed on screens. Fonts and metadata add further overhead.

1. 1

   Choose a compression tool

   Pick a browser-based compressor or a desktop editor with a Save as reduced size option.

2. 2

   Upload the PDF

   Drag your file into the tool. Files up to 100 MB compress quickly in most services.

3. 3

   Select a quality preset

   Choose Low, Medium or High. Medium is a great balance for most business documents.

4. 4

   Compress and preview

   Wait for processing and open the preview. Check that images and text still look sharp at normal zoom.

5. 5

   Download the smaller PDF

   Save the compressed file. Typical reductions range from 40% to 90% depending on content.

• Downsample images to 150 DPI for screen viewing.
• Remove embedded fonts you don't need with a desktop editor.
• Flatten form fields and annotations before compressing.
• Split very large PDFs first, then compress each part.

A well-compressed PDF is easier to send, faster to open and cheaper to store. Start with a medium preset, review the result, and adjust until you find the sweet spot between size and quality.