Free

Free Compress PDF Online

A free PDF compressor: shrink file size with honest structural compression — unused objects removed, metadata stripped.

Free tool · No sign-up · Private

The file never leaves your device — compression happens 100% in your browser.

Private by design. Compression runs on your device with pdf-lib. Nothing is uploaded, stored, or seen by anyone but you.

About this tool

About the Compress PDF

A PDF compressor shrinks bloated documents so they email cleanly and upload without errors. Drop your PDF into this free online tool and it applies honest structural compression: removing unused objects, stripping metadata, and cleaning up the file's internal structure — all in your browser, with your document never uploaded anywhere. Anyone who has bounced off a 25MB email attachment limit knows exactly why this exists.

Here is the honest part most compressors skip: results depend on what is inside. Text-heavy PDFs with embedded bloat can shrink dramatically, while scanned PDFs — which are really just stacks of page images — barely budge with structural compression and would need image downsampling instead. Your text and layout stay pixel-identical either way; nothing is re-rendered at lower quality. If your file barely shrinks, the tool tells you so rather than pretending otherwise.

Honest limits

What it does — and doesn't

No magic-ratio claims. Here's the truth about PDF compression.

Removes unused objects

PDFs accumulate dead objects — deleted pages, old revisions, orphaned fonts. The rebuild drops them, which can noticeably shrink sloppy files.

Strips metadata

Author names, creation dates, editing history, and producer tags are removed. Small savings, but a nice privacy bonus.

Won't shrink optimized PDFs much

A PDF that was exported cleanly is already tight. Expect small or zero savings — the tool tells you the exact result so there's no guessing.

Scanned PDFs barely change

Scans are mostly compressed image data. This tool never recompresses images, so scans come out essentially the same size — quality fully preserved.

How it works

Three steps to smaller files

Upload your PDF

Choose the PDF you want to shrink. It stays on your device — the tool reads it locally in your browser.

Run the compression

The PDF is rebuilt with packed object streams and its metadata is stripped. This takes seconds, even for big files.

Check the result

See the exact before-and-after sizes. If the savings are worth it, download the smaller file; if not, keep the original.

Use cases

When compression helps

Slim files travel better.

Beat email attachment limits

Gmail and most mail servers cap attachments around 25 MB. Trimming a bloated 28 MB report down to 19 MB gets it through.

Upload forms & portals

Government and job portals often limit uploads to 2–5 MB. A quick compression pass can get your documents under the cap.

Faster sharing on slow connections

A smaller PDF uploads faster on mobile data and opens quicker on older phones — worth it before sending to a WhatsApp group.

Strip metadata before sharing

Removing author names and creation dates is also a privacy win when you're sharing a document beyond its original audience.

FAQ

Compress PDF questions

How does this PDF compressor work?

It rebuilds your PDF through pdf-lib's object model, which packs objects into compressed streams, and strips embedded metadata (author, creation date, editing history). That's it — no image recompression, no quality tricks.

How much smaller will my PDF get?

Honest answer: it depends. Exported-from-Word or bloated generator PDFs often shrink noticeably. Already-optimized PDFs shrink a little. Scanned or image-heavy PDFs barely change, because their bulk is compressed image data we don't touch. The tool shows you the before/after sizes so you can judge for yourself.

Will compression hurt my PDF's quality?

No. This compressor never recompresses images or downsamples anything — pages look exactly the same. It only removes structural waste and metadata. If the tool says it saved 0%, your pages are untouched either way.

Why do scanned PDFs barely shrink?

Scanned pages are essentially photos, and their size is dominated by JPEG-compressed image data. Structural cleanup can't touch that data. To shrink scans you need image recompression, which always trades quality — we chose not to do that silently.

Is it free, and is my file private?

Yes to both. Free with no limits, no sign-up, no watermark — and the compression runs 100% in your browser, so your file is never uploaded or stored anywhere.

What if my PDF is password-protected?

Encrypted PDFs can't be processed by the browser, so they're rejected. Unlock the file first with a password you know, then compress the unlocked copy.

Why is my PDF so large and how do I shrink it?

Large PDFs are usually full of uncompressed images or leftover editing data. Structural compression removes the bloat and strips metadata — text-heavy files can shrink dramatically.

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