Compress PDF privately, without uploading it
PDFs are where the sensitive paperwork lives: contracts, payslips, bank statements, medical letters, passport scans. Uploading them to a PDF compressor site to get under a size limit means handing that paperwork to a company you know nothing about. Krisox compresses PDFs inside your browser tab instead, in the upload form you are already using.
Why it matters for PDF
Most online compressors and converters work by uploading your file to their servers, processing it there and sending a copy back. While it's there, it's covered by their privacy policy and retention rules, not yours, and it may pass through other companies' storage and networks.
PDFs can also hold more than you see: earlier versions of a design, private editing data from apps like Adobe Illustrator, and metadata about who made them and when.
How Krisox compresses PDF
- Attach the PDF in any upload form.
- Krisox shows the resulting size at each level. When levels would make the same file, it shows one size instead of a pointless choice.
- Click "Upload compressed", or download a copy to check first.
What changes, and what doesn't
- Images inside the PDF (scans, photos) are recompressed and resized to the level you choose. That is where almost all the savings come from.
- The file is restructured to store the same content more compactly, and duplicate images are stored once.
- Text, fonts and links are kept as they are, so text stays selectable and searchable.
- Adobe Illustrator's hidden editing copy, often most of an Illustrator PDF's size, is removed at Extreme and Recommended, and kept at Light. Krisox tells you when it finds one.
- Digitally signed PDFs and password-protected PDFs are never changed, so signatures stay valid.
- PDFs over 50 MB are left as they are by default, with a notice; you can raise that limit in Krisox settings.
Check it yourself
- Open Chrome's developer tools (Cmd+Option+I on a Mac, Ctrl+Shift+I on Windows) and choose the Network tab.
- Upload a file on any site and let Krisox compress or convert it.
- You'll see the website's own upload, and no request from Krisox carrying your file: Krisox never sends files anywhere.
Without Krisox
- Mac: open the PDF in Preview and use File → Export with the "Reduce File Size" Quartz filter. It can make scans blurry, so check the result.
- When exporting from Word, compress pictures first (Picture Format → Compress Pictures).
- Scan documents at 200 to 300 dpi in grayscale instead of high-resolution color.
Questions
My PDF is text only. Why does Krisox say there is little to gain?
Text-only PDFs are already compact; most of a big PDF's size is images. Krisox says so rather than offering levels that would all make the same file.
Can Krisox turn a PDF into images?
No. PDFs keep their format. Krisox can turn images into PDFs (Pro), not the other way round.
Is it free?
Compressing one PDF at a time is free. Compressing several at once is part of Krisox Pro.
Krisox is a browser extension for Chrome. Compressing one file at a time is free; converting formats and compressing several files at once are part of Krisox Pro.