Compress PDF — Reduce File Size Online
Reduce your PDF file size by removing metadata and optimizing the internal structure.
How It Works
- 1Upload your PDF by dragging it into the drop zone or clicking to browse.
- 2Pick a compression level to balance file size and quality.
- 3Click Download to save your compressed PDF.
About Compress PDF
PDF files can become unexpectedly large due to embedded metadata, unused objects, redundant internal structures, and unoptimized encoding. This is especially common with PDFs generated by word processors, design tools, and scanning software that embed extensive metadata and revision history. This tool reduces file size by stripping metadata (title, author, subject, keywords, creation date) and using object streams to consolidate and optimize the internal PDF structure. It works best on PDFs with bloated metadata or redundant internal objects — typical reductions range from 10% to 40% depending on the document. Common use cases include shrinking PDFs before email attachments, meeting upload size limits on web portals, reducing storage usage for document archives, and preparing files for faster download on websites. The compression is lossless, meaning the visual content, text, and layout remain identical to the original.
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Frequently Asked Questions
How much smaller will my PDF get?
Results vary. PDFs with lots of metadata or redundant internal objects see the biggest reduction. Heavily optimized PDFs may not shrink much. The tool shows the before and after file sizes.
Does compression reduce image quality?
This tool focuses on structural optimization (removing metadata, using object streams). It does not re-compress embedded images, so visual quality is preserved.
Will compression work on scanned PDFs?
Scanned PDFs are mostly raster image data, so structural optimization makes only a small dent. For scans, the highest-leverage move is reducing image resolution before producing the PDF; this tool can still strip redundant metadata on top of that.
Is my file uploaded to a server?
No. Transmute processes everything locally in your browser using JavaScript and the Canvas API. Your files never leave your device — there is no server, no upload, no cloud processing.
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