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PDF Compressor
100% LocalOptimize PDF documents client-side using object streaming.
PDF Compressor
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This tool runs entirely in your browser. Your input is never uploaded, logged, or sent to AllDevToolsHub or anyone else, and it keeps working offline once the page has loaded.
Upload a PDF. Object streaming optimization runs locally. Compare file sizes before downloading.
Learn More
The Mobile PDF Workflow: Scan, Sign, and Edit PDFs From Your Phone
Read Article
PDF Compression Trade-offs: Quality vs. File Size Explained
Learn how to shrink your PDFs without making them unreadable. Understand DPI, image downsampling, and font embedding to find the perfect balance for your documents.
Read Article
PDF Privacy: How to Scrub Metadata and Prevent Tracking
Read Article
Overview
What is PDF Compressor?
Reduce the file size of your PDF documents without uploading them to a server. Uses local compression algorithms to strip unused streams and metadata.
FAQ
Frequently Asked Questions
Reference
Technical Deep Dive
PDF Compressor
Reduce the file size of your PDF documents without uploading them to a server. Uses local compression algorithms to strip unused streams and metadata.
PDF-Native
Works with the real PDF specification, text, vectors, fonts, and metadata all preserved.
Stays Local
Documents never leave the browser, safe for confidential, regulated, or proprietary PDFs.
Surgical Precision
Targeted operations that don't re-encode or degrade the rest of the document.
01 Compression Filters Table
| Filter Type | Target Content | Efficiency |
|---|---|---|
FlateDecode | Text & Graphics | High (zlib) |
DCTDecode | Photographic Images | JPEG Variable |
JBIG2Decode | Monochrome Scans | Maximum |
LZWDecode | Legacy Assets | Low |
02 Optimization Pipeline
1
XRef Table Audit
The compressor builds a fresh Cross-Reference table, ensuring only active objects are included in the output.
2
Stream Injection
Uncompressed streams (often from raw scans) are wrapped in deflate filters to significantly reduce volume.
3
Metadata Stripping
Optional removal of bloated XMP metadata and proprietary third-party editor tags.
03 Compression Strategies and Quality Tradeoffs
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Image Downsampling Most PDF file size comes from embedded images. This tool applies JPEG recompression with configurable quality (60-90%) and optional DPI downsampling (from 300 DPI print quality to 150 DPI screen quality). A 10MB PDF with high-resolution photos typically compresses to 2-3MB at 72 DPI web quality with no visible degradation on screens.
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Client-Side Privacy PDF files often contain sensitive information, legal contracts, medical records, financial statements. This compressor runs entirely in your browser using WebAssembly-based PDF processing. Your documents never leave your device, unlike cloud-based compression services that upload your files to remote servers.
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RJRahul JalavadiyaFounder & Lead Engineer
Last reviewed 2026-07-29