Compress PDF
Rebuild and optimise a PDF to trim its size — entirely within your browser.
Compress PDF
This performs a safe, lossless rebuild (removing unused objects and re-serialising). For heavily image-based PDFs, converting the images separately gives bigger savings.
🔒 Your PDF is processed entirely inside your browser using JavaScript — it is never uploaded to any server.
🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.
Features
Shrink a PDF, keep it readable
Rebuilds the document with a tighter internal structure so it downloads and emails faster, with no visible quality loss.
Lossless rebuild
Removes unused objects and re-serialises the file — text stays crisp and pages are unchanged.
Private by design
The PDF is compressed in your browser and never uploaded, safe for confidential documents.
Before-and-after size
See the original size, compressed size and percentage saved so you know the result at a glance.
How it works — in four simple steps
No signup, nothing to install — it all runs in your browser.
Choose a PDF
Drag in or select the PDF you want to compress; the tool shows its current size.
Compress
Press Compress — the file is rebuilt locally with a more efficient structure.
Review the savings
Check the original vs compressed size and the percentage reduced.
Download
Download the smaller PDF, ready to send under an email or upload size limit.
How it works
PDFs accumulate overhead — unused objects, redundant metadata, and an inefficient internal layout — that inflates their size. Compressing rebuilds the file with a tighter structure so it downloads and emails faster, without changing how it looks.
Load your PDF and the tool re-parses it and re-serialises it using object streams, a compact way of packing the document's internal objects, then reports the before-and-after size. This is a safe, lossless optimisation: text stays sharp and pages are untouched.
Everything runs in your browser, so the file is never uploaded. Note that if most of a PDF's weight is high-resolution images, structural compression can only do so much — down-sampling or re-encoding those images (using an image compressor first) yields the biggest savings. Already-optimised PDFs may shrink little, which the tool will tell you.