PDF Compressor — Free Online, Shrink PDF Files
Compress PDF documents free online. Smaller file size for email and upload. In-browser, no upload, no signup, no watermark.
How to compress a PDF
Drop a PDF file.
Pick a render scale (lower = smaller file, lower quality) and JPG quality.
Click Compress. We render each page as JPG and rebuild the PDF — entirely in your browser.
Download the smaller PDF.
Why use a PDF compressor?
Smaller pdf files load faster, save bandwidth, and consume less storage. For websites, a good PDF compressor means faster page loads, better Core Web Vitals, better search rankings, and a noticeably better experience for visitors on mobile networks. For email, smaller attachments mean fewer rejections from mail providers and faster sends. For backups and archives, compressing pdf files lowers your cloud storage bill.
A PDF compressor is also a privacy tool. By stripping unnecessary metadata and re-encoding the pdf fresh, you remove identifying information that may have been embedded by the camera, scanner, or software that produced the original. Our PDF compressor strips embedded metadata by default so you can share or publish without leaking hidden details.
PDF files in particular are often produced at much higher quality than the use case requires. A photograph straight from a modern phone might be 8 MB; the same photo run through this PDF compressor at "good enough for the web" quality is often under 500 KB. The difference is invisible to most viewers but transformative for performance — and that is exactly the gap a great online PDF compressor should bridge.
How does the PDF compressor work?
When you drop a pdf file in, the PDF compressor loads it into memory inside your browser. Depending on the pdf format it then runs the appropriate browser API or WebAssembly engine — Canvas for images, FFmpeg for video and audio, pdf-lib for PDFs — to decode and re-encode the pdf at your chosen quality level. There is no upload step at any point.
The output is a fresh pdf file with the new (smaller) size. The original is not modified, and nothing leaves your device. You can compare input and output sizes side by side in the result panel before downloading the compressed pdf.
Typical results from this PDF compressor: 50–80% reduction for images and audio with no perceivable quality loss; 30–60% reduction for typical video clips by adjusting the constant rate factor (CRF). PDFs vary widely — text-heavy PDFs shrink less, image-heavy PDFs shrink dramatically.
Tips for the best PDF compressor balance
Pick a quality preset that matches how the pdf will be used. For web, prioritize size; for archive, prioritize quality. The presets in this PDF compressor are labelled with their typical use case so you do not have to guess.
If the compressed pdf is too small or too soft, raise the quality slider and re-run the PDF compressor. The original is still in your input box. Online compression is fast enough that experimenting is cheap.
For maximum pdf compression, combine quality reduction with dimension reduction. A 1920×1080 image scaled to 1280×720 and re-encoded at 75% quality through the PDF compressor is dramatically smaller than the same image at 95% quality and full resolution — and for most online use cases, the visible difference is zero.
For batch pdf compression, this PDF compressor accepts up to five files at once. Each file is processed independently and shown with its own size delta and download button. A "Download all as ZIP" button packages the batch.
Frequently asked questions
Is this PDF compressor free?
Yes. The PDF compressor is 100% free: no signup, no watermark, no daily limit. It is funded by display advertising, never by selling your pdf files or data.
Will the PDF compressor reduce pdf quality?
It depends on how much you compress. Mild compression (around 80% quality for images, CRF 23 for video) is visually indistinguishable from the original pdf to most viewers. Aggressive compression introduces artifacts that may or may not matter for your use case. Try a setting and download a sample before committing.
Is it safe to compress pdf online here?
Yes. The PDF compressor runs entirely in your browser. PDF files never leave your device. There is no upload, no cloud processing, and no log of what you compressed.
How much can the PDF compressor shrink my file?
It depends on the original pdf. A high-quality photo can usually be reduced 50–80% with mild visible quality loss. A PNG containing a screenshot may shrink less because it is already efficiently compressed for that content type. Audio and video reduction varies by source bitrate.
Can I batch compress pdf files?
Yes — the PDF compressor accepts up to five pdf files at a time. Each file is processed individually and listed with its own size delta and download button.
Do you keep a copy of my compressed pdf?
No. We do not have a server that sees your pdf files. The PDF compressor runs entirely in your browser, so there is nothing for us to store.
Why is the result slightly different from another pdf compressor?
Different pdf compressors use different encoders, defaults, and metadata handling. Our defaults aim for a good balance of size and quality, but minor differences from another tool are normal even at the same quality setting.
Can I use this PDF compressor on a phone?
Yes. The PDF compressor is fully responsive and works on iOS Safari and Android Chrome. You can compress pdf files straight from your phone storage and save the result back to downloads.