Zero quality loss
Nothing is re-encoded: images, fonts and vectors are copied through as they are. The savings come from structure, not from degrading your pages, so output is pixel-identical.
Compress PDF
Shrink PDF files by rewriting them with compressed object streams.
- Upload
- Batch upload supported · 40 MB max
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
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The tool is loading its code on your device. This happens once and is cached for later visits.
Processed entirely on your device
Your file is read, transformed and re-encoded inside this browser tab using JavaScript. There is no upload endpoint — nothing leaves your machine, nothing is stored, and the result is created as a local object URL that disappears when you close the page.
Overview
About the Compress PDF
Compress PDF files free online without touching page quality. Metadata is stripped and the file is rewritten with object streams — the size saving is shown up front.
Most PDFs are larger than they need to be, and almost none of the waste is in the pages you see. It is in the structure: uncompressed cross-reference tables, one object per line, duplicated metadata and producer baggage accumulated across every application that ever saved the file.
What this tool actually does
The document is parsed and rewritten with pdf-lib using compressed object streams — many small objects packed into a few deflated streams instead of thousands of plaintext lines — and the metadata dictionary is cleared. Pages, images and fonts are copied through byte-for-byte, which is why the visual result is identical and the operation is fast.
Which files benefit most
- Exports from office suites and scanners, which write verbose, uncompressed structures.
- Documents that have been merged, annotated or re-saved many times, accumulating producer history.
- Forms and reports with large object counts relative to their page count.
Which files barely change
PDFs that were already written with object streams — most modern print-shop and LaTeX output — have little structural waste left. The honest answer for those is that they are already small, and the size delta shown per file says so plainly.
A note on metadata
Clearing title, author, subject and keywords is part of the rewrite. If you need those fields preserved, edit them back afterwards; if you were compressing partly to scrub a document's history before sharing, this does that for free.
Step by step
How to use the Compress PDF
Drop one or more PDFs onto the upload area, or click it to browse.
Press Compress PDF — each file is rewritten locally with compressed object streams.
Compare the before and after sizes in the result rows and the summary strip.
Download the compressed files; page content is untouched.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
Honest about the saving
Files that are already optimised shrink little, and the tool shows that instead of claiming a win. Documents bloated by metadata and uncompressed object streams shrink dramatically.
Metadata stripped
Title, subject, keywords and producer information are cleared on rewrite — useful when a document's hidden history should not travel with it.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
How much smaller will my PDF get?
It depends entirely on how the file was written. Documents from word processors and scanners with uncompressed cross-reference tables and embedded metadata often shrink 20–40%. Files that were already optimised may shrink only a few percent, and the result row shows the real number.
Does compression reduce image quality?
No. This tool never re-encodes images or fonts; it rewrites the document structure around them with compressed object streams. If you need images re-encoded smaller, that is a different, lossy operation.
Why did my file get slightly bigger?
Rarely, a PDF that was already written with optimal object streams gains a little from the rewrite. The size delta is displayed for every file, so you can simply keep the original in that case.