PDF Compress
100% Private & Local — Your files NEVER leave your device

PDF Compressor

Reduce your PDF file size directly in your browser. No upload required. Choose your compression level.

Drop your PDF here

or click to browse

Max 200 MB

How PDF Compression Works — and Why Privacy Matters

Most online PDF compressors — iLovePDF, SmallPDF, Adobe Acrobat Web — require you to upload your file to a remote server. Your confidential contracts, medical records, and financial statements travel over the internet and may be temporarily stored on third-party infrastructure. This tool is different: all three compression modes run entirely in your browser using pdf-lib and pdf.js, two widely-used open-source JavaScript libraries.

The Quick mode re-saves the PDF with optimized object streams, most effective for files with redundant metadata or cross-reference tables. The Balanced and Maximum modes go further: they rasterize each page to a JPEG image and embed those images into a new PDF. This achieves dramatic size reduction for scanned documents and image-heavy PDFs, at the cost of text selectability.

Nothing is transmitted — open your browser's DevTools Network tab while compressing and you will see zero upload requests. The tool even works offline once the page has loaded.

Frequently Asked Questions

How much can this tool compress a PDF?
It depends heavily on the content. For scanned documents or image-heavy PDFs, Balanced mode typically achieves 50–80% reduction and Maximum mode can reach 85–95%. For text-only or already-optimized PDFs, Quick mode may yield 5–20% savings, while rasterization modes actually increase the size in some cases (since converting sharp vector text to JPEG is not always beneficial). The before/after comparison is shown so you can judge the result immediately.
What is the difference between text PDFs and scanned PDFs?
A text PDF contains vector instructions for drawing glyphs, meaning it's already highly compact. Quick mode (metadata re-save) works best here. A scanned PDF is essentially photos of pages — large JPEG or TIFF images embedded in a PDF wrapper. Balanced and Maximum modes shine here, re-compressing those images with adjustable quality settings. As a rule of thumb: if you can select text in your PDF, it's a text PDF. If text appears as a blurry image, it's scanned.
Is my file really private? Where does it go?
Your file stays entirely on your device. The page loads JavaScript libraries from CDNs once, then does all processing inside your browser's engine. Not even the filename is sent to any server. You can verify this yourself: open DevTools → Network tab, then compress a PDF — you'll see zero outbound file uploads.
Will compression reduce quality or damage my PDF?
Quick mode is lossless — it only reorganizes internal PDF structures, so content is identical. Balanced and Maximum modes are lossy: pages are converted to JPEG images at adjustable quality, so some sharpness may be lost, and text will no longer be selectable or copyable in the output file. Maximum mode uses aggressive JPEG compression which may produce visible artifacts on high-contrast edges. Your original file is never modified — the download is always a new, separate file.
What are the alternatives if browser compression isn't enough?
For professional compression that preserves text selectability and reduces embedded font data, desktop tools like Ghostscript (free, command-line), Adobe Acrobat Pro, or Preview on macOS (Export as PDF → Quartz Filter → Reduce File Size) are excellent. Ghostscript's PDF optimizer is particularly powerful: gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -o out.pdf in.pdf
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