Compress PDF Files Online
Reduce PDF file size without losing quality. Choose lossless structure optimization or image-based compression for maximum savings.
How to Compress a PDF
Upload Your PDF
Click the upload area or drag and drop your PDF. The tool reads the page count instantly — no waiting for a server.
Choose Compression Level
Pick Lossless (preserves text), Balanced (good quality, big savings), or Maximum (smallest file possible).
Download Compressed PDF
See the before/after file size, then download your optimized PDF immediately. No email or signup needed.
Frequently Asked Questions
How much can I reduce a PDF file size?
It depends on the PDF content. Lossless compression typically saves 5–20%. Image-based compression (Balanced/Maximum) can reduce file size by 50–90%, especially for scanned documents or PDFs with many images.
What is the difference between lossless and image compression?
Lossless compression removes redundant PDF structure data — text stays searchable and quality is identical. Image-based compression renders each page as a JPEG, which is much smaller but text becomes non-selectable.
Will compressing a PDF reduce its quality?
Lossless compression has zero quality impact. Balanced and Maximum modes render pages as JPEG images — visual quality is very good at Balanced, lower at Maximum. Choose based on your use case.
Is it safe to compress PDFs online with PDFForge?
Yes — completely safe. All processing runs locally in your browser using WebAssembly and the Canvas API. Your PDF is never uploaded to any server. We have no access to your files.
Why is my compressed PDF larger than the original?
This can happen with very small or already-optimized PDFs. If lossless compression increases the size, that PDF is already well-compressed. Try Balanced compression instead, or if the original is already tiny, no action is needed.
Can I compress a password-protected PDF?
PDFs with owner passwords (editing/printing restrictions) can usually be compressed. PDFs requiring a password to open must be unlocked first — use our free Unlock PDF tool.
Does compression work on scanned PDFs?
Yes! Scanned PDFs are image-heavy and often compress very well with Balanced or Maximum mode, sometimes achieving 70–85% size reduction.