What's the difference between 'Strong Compression' and 'Lossless Optimization'?

Lossless Optimization only reorganizes the file structure and strips metadata. Text remains selectable and searchable, but there's little change in file size for already optimized files. Strong Compression renders each page as an image and re-encodes it, significantly reducing file size at the cost of text becoming images and no longer selectable or searchable.

Can text still be selected or searched after compression?

Yes, in Lossless Optimization mode; no, in Strong Compression mode, because pages have been converted to images. If you need to preserve selectable text, use Lossless Optimization.

Why do some PDFs barely reduce in size after compression?

If the file is already optimized or consists mainly of text/vectors, Lossless Optimization has limited effect. In such cases, switch to Strong Compression and select a lower image quality for smaller size.

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FAQ

Absolutely safe. All processing is done in your browser. The PDF file never leaves your device and is not uploaded to any server.

What is PDF Compression?

PDF compression is the process of reducing file size while maintaining readability as much as possible, making it easier to send via email attachments, web uploads, or instant messaging. PDFs that are too large are often difficult to share due to high image resolution, many embedded fonts, or redundant metadata, and compression can effectively solve this problem.

This tool offers two modes: Lossless optimization only reorganizes file structure and removes metadata, leaving text selectable and searchable; strong compression renders each page as an image and then encodes it, significantly reducing size, suitable for scanned documents. You can flexibly balance clarity and size based on your needs.

How to Compress PDF Files

1Upload or drag in the PDF file that needs compression.
2Choose the compression method: lossless optimization or strong compression.
3When selecting strong compression, you can further adjust image quality to control the file size.
4Click 'Compress PDF', and after completion, view the savings ratio and download the result.

Why Choose Our Compression Tool

Privacy First: Compression is performed entirely locally in the browser, with files not uploaded to any server.

Dual Modes Available: Lossless optimization preserves selectable text, while strong compression aims for minimal file size.

Free and Unlimited: No file size limit, no watermarks, and reusable.