PDF Compressor

Reduce PDF file size by optimizing its internal structure. Runs entirely in your browser via a background thread — your files never leave your device.

Optimization Profile

Drag & drop your file here

or click to browse · Accepts PDF · Max 50MB

Free Browser-Based PDF Compression Tool

Large PDF files can be a hassle to email, share, or upload. Our free PDF Compressorreduces file size by optimizing the PDF's internal structure — entirely within your browser. Your file is never uploaded to any server, making this one of the most privacy-respecting PDF compression tools available online.

How Browser-Based PDF Compression Works

This tool uses pdf-lib, a JavaScript library that parses and rewrites PDFs directly on your device. Processing runs in a dedicated background thread (Web Worker), so your browser stays fully responsive during compression — no freezing, no stuttering, even on large files. Compression works by enabling object streams (which pack multiple PDF objects into compressed streams) and removing unnecessary metadata. This is lossless compression — no image quality is reduced and no content is altered.

Why Compress Your PDFs?

  • Faster Sharing: Send documents via email without hitting attachment size limits.
  • Better Web Performance: Smaller PDFs hosted on websites load faster and improve user experience.
  • Save Storage Space: Optimize archived documents to free up hard drive or cloud storage.
  • Faster Uploads: Government portals and legal filing systems often impose strict file size limits.

Understanding the Optimization Profiles

  • Web Profile: Strips all metadata (title, author, subject, keywords, creator, and producer fields) and applies object stream compression. Best for PDFs shared publicly where metadata is irrelevant.
  • Print Profile: Strips only technical metadata (creator and producer) while preserving author and title. A good balance for office documents that need to retain authorship information.
  • Prepress Profile: Applies object stream compression only, leaving all metadata intact. Intended for professional print workflows where complete document metadata is required.

Limitations to Be Aware Of

Because this tool runs in the browser without a server, it cannot recompress or downsample embedded images — which are typically the largest component of a PDF. For PDFs containing many high-resolution images, the size reduction will be modest. For PDFs that are primarily text, the savings can be more significant. If you need aggressive image-level compression, a server-side tool using Ghostscript will produce better results at the cost of privacy.