About Compress PDF
Compress PDF shrinks a document by rendering every page with pdf.js and re-embedding it as a JPEG at the quality you pick, so scan-heavy and photo-heavy files come out dramatically lighter. That trade-off is the entire mechanism: it makes pictures cheaper, not text. Reach for it to get a scanned contract under an email attachment limit, to squeeze a photo-rich brochure into an upload form that rejects large files, to lighten a slide deck full of screenshots before archiving it, or to slim down a bundle of phone-scanned receipts. If you were looking for how to shrink a PDF, reduce PDF file size or make a PDF smaller online, this is that tool — and nothing is saved unless the result really is smaller than what you started with.
Compress PDF specs
| Price | Free ($0) — no paid tier |
|---|---|
| Account | Not required |
| Watermark | None |
| Where it runs | In your browser, on your device |
| File upload | No file is uploaded |
| Input | PDF (1 file) |
| Output | |
| File size limit | Limited only by your device's memory |
| Works offline after the page loads | Yes |
How to use Compress PDF
Drop the PDF in
Drag a single file onto the Drop your PDF here or click to browse area. Its name and size appear in a card, and a Sample page at chosen quality preview loads underneath.
Pick a quality preset
Choose the High (90% — best looks), Medium (75% — balanced) or Low (50% — smallest) chip. The note below them warns that pages are rasterized to JPEG at every preset, so the selectable text layer is replaced.
Decide about metadata
Remove metadata (title, author, subject, keywords, producer, creator) is ticked by default. Untick it to carry those six fields plus the creation and modification dates over from the original.
Check the sample page
The preview re-renders at the selected quality. Page through it and confirm the smallest type is still legible — changing any setting clears the previous result so you never download a stale file.
Compress and download
Press Compress & download. The file saves with a -compressed suffix only when it genuinely came out smaller; if it did not, an amber panel shows both sizes and offers Download anyway.
Frequently asked questions about Compress PDF
Why didn't my PDF get any smaller?
A PDF only shrinks under this tool when its pages are expensive to draw, and text-only pages are not. Compress PDF turns each page into a JPEG photograph of that page, so a document that was a few kilobytes of font instructions and vector lines becomes a full-page image and can easily end up larger than it started. That is why the tool compares the two sizes before saving anything: when the compressed file is not smaller, nothing downloads, an amber panel shows the original and compressed sizes side by side, and you can still choose Download anyway if you want the rasterized version for another reason. For text-heavy files, keep the original — or try Remove blank PDF pages if the bulk comes from empty scanned sheets.
What does compressing do to the text in my PDF?
Compressing replaces the selectable text layer with a picture of the text. Every page is rendered by pdf.js at the preset's scale, encoded as a JPEG, and drawn into a brand-new page of the original dimensions, so afterwards a reader sees identical-looking type but searching or copy-pasting finds nothing at all. The tool states this under the quality chips rather than letting you discover it after the fact. If you need the words back, run the compressed file through OCR PDF, which recognises the characters in the image and lays an invisible text layer over them. If searchable text matters more than size, skip compression and trim pages you do not need instead.
Which quality preset should I pick — High, Medium or Low?
High is the safe default for anything with small type; Low is for archive copies of photo-heavy documents. The three chips change two things at once: the scale each page is rendered at and the JPEG quality it is saved with. High renders at 1.5x and saves at 90% quality, Medium at 1.25x and 75%, Low at 1x and 50%. More scale means more pixels per page, so fine print stays crisp but the file stays bigger; lower quality means blockier edges around letters and stronger artefacts around photographs. The Sample page at chosen quality preview re-renders whenever you switch chips, so the quickest way to decide is to look at the smallest text on a representative page.
Does compressing a PDF strip the author name and other properties?
Compress PDF strips those document properties by default, because the Remove metadata box starts ticked. The compressed copy is then written with empty title, author, subject, keywords, producer and creator entries. Untick the box and the tool re-reads those six fields from the original, along with the creation and modification dates, and writes them back verbatim. Because the compressed document is built from scratch rather than edited in place, nothing carries over implicitly; every field you keep is copied on purpose. If a field in the source is malformed and cannot be read, the tool tells you the metadata could not be copied instead of silently shipping half of it. To set specific values afterwards, use Edit PDF metadata.
Are bookmarks, links and form fields kept?
No — bookmarks, hyperlinks and form fields are all lost when a PDF is compressed here. Each page becomes a flat JPEG inside a freshly created document, so the source's outline, its interactive fields, its comments and its annotations have nothing left to attach to and are simply left behind. That is a real cost, and it is why this is the wrong first choice for an interactive document. If you need those structures kept, change page geometry with Resize PDF, bake filled values in with Flatten PDF, or delete unneeded pages instead — all of those rewrite the existing document rather than rebuilding it out of images. Page count, page order and the physical page dimensions are the only things that survive a compression unchanged.
Is Compress PDF free, and does my file get uploaded anywhere?
Compress PDF is free with no signup, no usage cap and no watermark, and nothing you drop on it is uploaded. The rendering, the JPEG encoding and the rebuild all happen in your own browser tab through pdf.js and pdf-lib; the file is read from disk with the browser's File API and the result is written straight back to your downloads folder. You can confirm that yourself — open your browser's network panel, run a compression, and you will not see the document leave. The practical ceiling is your device's memory rather than a server quota, which is why a very large scan is slower on a phone than on a laptop.
Why in-browser processing matters
Every PDFChamp tool runs inside this page: the file you choose is read by JavaScript in your own browser and is never sent to a server, so nothing is uploaded, queued, or stored anywhere. That removes the upload wait, the processing queue, and the question of what happens to your file afterwards — the about page compares this architecture with server-side PDF tools.
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