ConvertSwift
Browse Tools
100% Secure: Files are processed in your browser memory and never uploaded.

Free Online PDF Compressor

Reduce the file size of your PDF documents locally. Compress receipts, contracts, and portfolios without server lag.

Drag & drop PDF files here or click to browse

Supports compression limits up to 100 MB
Low Compression
High image quality
Recommended
Optimal size & quality
High Compression
Minimum file size

Why compress PDF documents locally?

PDF documents often contain confidential information, such as financial reports, contract terms, signatures, or personal records. Standard online PDF compressors require you to upload your files to their servers, creating a major privacy risk.

ConvertSwift runs entirely in-browser. All text assets, structures, and image scaling happen locally in memory, meaning your files never leave your computer.

How does browser-based PDF compression work?

In Phase 2, the PDF compression engine leverages high-performance WASM builds to analyze the document structure. It optimizes text streams, downsamples image resolutions, and flattens embedded file assets to achieve maximum size reduction entirely inside your browser tab.