How to Effectively Compress a PDF Online
Published: 2025-06-01 · Updated: 2025-07-02
PDF files can get very large, especially when they contain high-resolution images, scanned documents or embedded fonts. PDF compression can reduce file size by up to 80%, making it easier to email, store in the cloud and share. In this guide we will show you how to effectively compress PDF files using the free OptimaPDF tool.
What is PDF Compression?
PDF compression is the process of reducing PDF file size by optimizing images, removing unnecessary metadata and applying more efficient encoding methods. OptimaPDF offers three compression levels — from light optimization to aggressive size reduction.
How to Compress a PDF Step by Step
Choose the Compression Level
Low — minimal quality loss, moderate size reduction. Recommended — balanced quality-to-size ratio, best for everyday use. Extreme — maximum reduction, for files that need to be as small as possible. Recommended is selected by default and is the optimal choice in most cases.
Drop the PDF File into the Upload Area
You can also click the upload area to open a dialog and select a file from your disk. PDF files of any size are supported — all operations are performed locally in your browser.
Click "Compress PDF"
The compression process usually takes a few seconds. Once complete you will see a preview with information about the file size reduction. You can download the compressed PDF immediately by clicking the download button.
When to Use Each Compression Level?
- Low: text documents that will be printed — quality remains nearly identical to the original
- Recommended: everyday file sharing — good balance between size and quality
- Extreme: email attachments and archiving — greatest reduction at the cost of image quality