What Is PDF Compressor?
PDF Compressor shrinks PDFs by redrawing every page as a JPEG image at the resolution and quality you pick. That works well on scanned documents and image-heavy files, where it often cuts the size sharply. The trade-off is real: the output is images of your pages, so text can no longer be selected, searched or read aloud by a screen reader, and links, form fields and bookmarks are dropped. Keep the original if you need any of those.
How to Use This Tool
Upload your PDF and choose a preset (Maximum 72 DPI, Balanced 108 DPI, Minimum 144 DPI) or set the DPI and JPEG quality yourself. The preview shows the top-left corner of page 1 at twice its size, original next to compressed, with the size page 1 would take. Then click Compress. The tool processes your file in-browser using client-side JavaScript, then provides a download link with the compressed result. You’ll see the before-and-after file sizes so you can gauge the reduction.
Why Use PDF Compressor?
Most online compressors upload your files to remote servers, creating privacy risks for sensitive documents. This tool runs entirely in your browser — no data leaves your device. The tool sets no file size cap (very large files are limited by your device's memory), adds no watermark and needs no account. For a detailed walkthrough, see our step-by-step guide.
Desktop tools like Acrobat or Ghostscript can recompress only the images inside a PDF and leave text as text. This tool takes the simpler route that a browser can do reliably: it renders each page with PDF.js, saves it as a JPEG and rebuilds the PDF with pdf-lib, keeping each page's original size and the document's title and author. That is ideal for scans, which are images already, and a poor fit for text-heavy reports, which may even come out larger. The point of running it locally is privacy: scanned tax returns, signed contracts and medical records never leave your device.
Frequently Asked Questions
How does browser-based PDF compression work?+
The tool renders each page to a canvas at the DPI you choose, saves it as a JPEG at the quality you choose, and rebuilds the PDF from those images at the original page size. Text becomes part of the image, so it is only as sharp as the DPI allows and can no longer be selected or searched.
Will compression reduce my PDF quality?+
Yes, to a degree you control. DPI sets how much detail each page keeps (72 is screen quality, 144 is good for zooming in, 300 is print quality) and JPEG quality sets how much compression noise appears. The side-by-side preview shows the result on page 1 before you compress.
Is my PDF uploaded to a server?+
No. Everything runs in your browser. Your files stay on your device.
How much can I expect to shrink a PDF?+
It depends on what is inside. Scans and photo-heavy PDFs usually shrink a lot, because the tool replaces large images with smaller ones. Text-only PDFs can come out larger, because a page of text stored as text is tiny compared with a picture of that page; the tool tells you when that happens so you can keep the original.
Does compression reduce text quality?+
Yes. Every page, text included, is turned into a JPEG, so text is as sharp as the DPI you pick, and it stops being selectable, searchable or readable by screen readers. For text-heavy documents where that matters, keep the original or use a desktop tool that recompresses only the images.
Which compression level should I pick?+
Balanced (108 DPI, JPEG quality 65) suits email and on-screen reading. Minimum compression (144 DPI, quality 82) keeps small print legible when zoomed. Maximum (72 DPI, quality 40) gives the smallest file and suits documents read at normal size on screen. For printing, set about 200 to 300 DPI with the slider.
Can I batch-compress multiple PDFs?+
Not at the moment: the tool handles one PDF at a time. Compress, download, then choose Compress Another for the next file; the DPI and quality settings stay as you left them.
Does compression strip metadata?+
Mostly. The rebuilt PDF keeps the title and author. Everything else is left behind: other metadata fields, XMP, bookmarks, links, form fields, attachments and any digital signature. The producer field reads pdf-lib.
Built by Derek Giordano · Part of Ultimate Design Tools
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