PDF Compressor
Shrink PDF file size locally in your browser. Text PDFs are optimized while keeping text selectable; scans can be flattened to images for the smallest size. Nothing is uploaded.
Drop your PDFs here
or choose files — nothing is uploaded
Up to 10 PDF files, 100 MB each. Encrypted PDFs must be unlocked first.
No PDFs yet.
Compression runs entirely in your browser — your PDFs never leave your device.
How to use
- Drop your PDFs into the box or click “Choose PDFs” (up to 10 files).
- Each file is analyzed automatically and marked as text or scanned.
- Adjust the strength slider — it controls both the vector profile and the rasterize DPI/quality.
- Click “Compress PDFs”, then download the results individually or all at once.
Details
How it works
Text PDFs are re-processed by a WebAssembly build of Ghostscript (the industry-standard PDF interpreter, AGPL-licensed) with the pdfwrite device: fonts are subset and re-embedded, duplicate images are detected, image resolution is capped, and streams are recompressed. Scans are rendered page by page with PDF.js and rebuilt as JPEG pages. Everything runs inside a Web Worker on your device.
Strength slider
The single slider maps to both engines. The left half keeps higher quality (up to 288 DPI and 100% JPEG quality for rasterization); the right half trades quality for size (down to 72 DPI and 40% quality). The vector engine maps the same value onto the prepress / printer / ebook / screen profiles.
What rasterize mode loses
Flattening pages to images removes selectable text, search, links, and form fields. Bookmarks can optionally be preserved. Use it for scans or when the smallest possible size matters more than text selection.
Privacy
No uploads, no telemetry, no storage. Your PDFs are processed in your browser's memory and disappear when you close or reload the page.
FAQ
Are my PDFs uploaded anywhere?
No. Both compression engines — the vector optimizer and the page rasterizer — run entirely in your browser as WebAssembly. No file data is ever sent to a server.
What is the difference between vector and rasterize compression?
Vector compression re-optimizes the PDF structure: fonts are subset, duplicate images are detected, and resolution is capped. Text stays selectable. Rasterize mode converts every page into an image, which usually shrinks files the most but makes text unselectable and drops links and forms.
How is the mode chosen for my file?
After upload, the first pages are sampled to detect whether the PDF is a digital text document or a scan. Text PDFs use vector compression; scans use rasterize mode. You can force rasterize mode for maximum reduction.
Why does my file show “Already optimal”?
If the compressed result is not smaller than the original, the tool honestly returns your original file instead of pretending to save space. Well-optimized PDFs often cannot be reduced further without visible quality loss.
Can I keep some pages uncompressed?
Yes. List page numbers (e.g. 1,2 or 1-5) in “Pages to skip”. Those pages are copied from the original document unchanged; all other pages are compressed.
Are password-protected PDFs supported?
No. Encrypted PDFs must be unlocked before compression, otherwise the file cannot be parsed in the browser.