Compress PDF Files Online — Free

PDF compression is essential for anyone working with document-heavy workflows. Large PDF files can be problematic when sharing via email, uploading to websites, or storing in cloud services with limited space. Our PDF compressor uses Ghostscript — the same engine professional publishing houses rely on — to reduce file size by up to 90% while keeping text crisp and selectable.

The compression process works by downsampling embedded images, removing duplicate resources, and streamlining the internal document structure. Unlike simple downsampling tools that re-encode everything as JPEG, our pipeline only re-encodes raster content where doing so yields a real saving. Text is stored as vector outlines or character codes referencing embedded fonts — neither is touched by image compression — so text-heavy documents keep their crisp readability while image-laden files see the most dramatic size reductions.

Choosing the right compression level. You pick the preset before you upload — no waiting for the file to process before you can see your options. Maximum (Screen) downsamples images to 72 DPI, the resolution of on-screen viewing. It produces the smallest files and is the right choice when the PDF will only ever be read on a screen — email attachments, web uploads, chat-app sharing. High (eBook), the recommended default, downsamples to 150 DPI: still comfortably sharp on tablets and laptops, usually 50–80% smaller than the original for scanned or image-heavy documents. Medium (Printer) keeps images at 300 DPI so the document survives a trip through a home or office printer without visible softening. Minimal (Prepress) also targets 300 DPI but additionally preserves color accuracy for professional printing — choose it when a print shop will handle the file.

What results to expect. Savings depend almost entirely on what is inside the PDF. Scanned documents, photo-rich reports, and catalogs typically shrink 50–90% because page scans are large raster images with plenty of redundancy to remove. Text-mostly PDFs exported from Word or Google Docs usually shrink 10–30% — there is simply less image data to optimize. And a PDF that has already been compressed once may barely change at all; that is not a failure, it means the file was already efficient. As a rule of thumb: if your 10-page scanned contract weighs 25 MB, the eBook preset will usually bring it comfortably under a 10 MB email cap, and the Screen preset well below that.

Your data stays yours. Files are transferred over HTTPS, processed in an isolated server-side directory, and automatically deleted within two hours. The download card also includes a "Delete file now" button if you want the original and the compressed copy wiped immediately. We never index, share, or repurpose your documents.

Compression preserves the things that make a PDF useful: hyperlinks keep working, bookmarks survive, form fields stay fillable, and tagged structure for accessibility remains intact. Once your file is smaller, you may also want to merge several PDFs into one, split out specific pages, convert the document to an editable Word file with PDF to Word, or turn images into PDFs with JPG to PDF. The full catalog of 17 utilities lives on the PDF tools hub.