How much smaller will it be?

Savings depend on the PDF. Structure optimization helps most with PDFs that have redundant objects; image-heavy PDFs see smaller gains.

Will this reduce the quality of images in my PDF?

No — this uses structural compression (optimizing how the PDF's internal objects are stored), not image recompression, so visual quality is preserved. For PDFs that are mostly large embedded images, size reduction will be more limited than for text-heavy or structurally redundant documents.

Is my PDF uploaded to a server during compression?

No — the entire compression process happens locally in your browser, so your document never leaves your device.

Can I compress a PDF that's already been compressed once?

Yes, though a PDF that's already well-optimized may see minimal additional savings on a second pass, since there's less redundant structure left to remove.

Will this work on scanned document PDFs?

It will process them without error, but scanned PDFs are typically dominated by embedded page images rather than redundant structure, so expect smaller size reductions compared to text-based or structurally redundant PDFs.

Compress PDF

Reduce PDF file size while keeping good quality.

TL;DR: Compress PDF is a free, browser-based tool that lets you reduce PDF file size while keeping good quality.

Drop a PDF here

or click to browse

This re-saves and optimizes the PDF structure (object streams). Savings vary by file.

About the Compress PDF

Compress PDF reduces document file sizes by applying modern Deflate/Flate stream compression algorithms, re-sampling high-resolution embedded raster graphics (such as scanned invoices or camera photos), and stripping unreferenced metadata, thumbnail caches, and duplicate embedded font subsets.

How to Use the Compress PDF

Drop your large PDF document into the compression engine.
Select your target compression tier: Low (maximum clarity), Medium (optimal for email and web), or High (maximum byte reduction).
Click 'Compress PDF' to execute stream filtering and image downsampling directly in WebAssembly/JavaScript.
Compare original vs. compressed file size and download your optimized document.

The Physics of PDF Stream Compression

PDF file size is dominated by uncompressed XObject image streams and redundant metadata. Compression applies Flate/JBIG2/DCT stream filters and downsamples image resolution to 150 DPI for standard screen viewing, drastically lowering byte overhead without visible degradation.

Expert Tips for Compress PDF

Vector Text Remains Crisp: Compression primarily optimizes embedded raster images and stream filters; vector text and typography retain infinite crispness.
Scanned Document Optimization: Scanned documents with 300+ DPI color images typically achieve 60%–85% file size reductions.
Email Attachment Threshold: Use Medium compression to ensure documents stay safely below standard 20MB corporate email attachment limits.

Related Guides & Tutorials

Compress Images Without Losing Quality — Learn in-depth concepts, best practices, and expert tips.
Compress Pdf Without Losing Quality — Learn in-depth concepts, best practices, and expert tips.
How To Compress Images Without Losing Quality — Learn in-depth concepts, best practices, and expert tips.

100% Client-Side Privacy Guarantee

All processing runs locally inside your browser using JavaScript and HTML5 APIs. Your data, files, and inputs are never uploaded to any remote server. Complete privacy by design.

Frequently Asked Questions

: Savings depend on the PDF. Structure optimization helps most with PDFs that have redundant objects; image-heavy PDFs see smaller gains.
: No — this uses structural compression (optimizing how the PDF's internal objects are stored), not image recompression, so visual quality is preserved. For PDFs that are mostly large embedded images, size reduction will be more limited than for text-heavy or structurally redundant documents.
: No — the entire compression process happens locally in your browser, so your document never leaves your device.
: Yes, though a PDF that's already well-optimized may see minimal additional savings on a second pass, since there's less redundant structure left to remove.
: It will process them without error, but scanned PDFs are typically dominated by embedded page images rather than redundant structure, so expect smaller size reductions compared to text-based or structurally redundant PDFs.

Cite This Tool

Referencing this tool in a paper, article, or bibliography? Copy a ready-made citation below.

NexLove.org. (2026). Compress PDF [Software]. https://nexlove.org/tools/compress-pdf.html

“Compress PDF.” NexLove.org, 2026, nexlove.org/tools/compress-pdf.html.

NexLove.org (2026) Compress PDF. Available at: https://nexlove.org/tools/compress-pdf.html (Accessed: 2026).

@misc{nexlove_compress_pdf,
  title = {Compress PDF},
  author = {{NexLove.org}},
  year = {2026},
  url = {https://nexlove.org/tools/compress-pdf.html}
}

Embed This Tool

Add the live Compress PDF tool to your own website with this snippet — it loads the real, working tool in an iframe, not a static screenshot.

<iframe src="https://nexlove.org/embed/compress-pdf.html" width="100%" height="600" style="border:1px solid #e2e8f0;border-radius:12px" title="Compress PDF — NexLove.org" loading="lazy"></iframe>

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