How this tool works
Compress PDF: a practical guide
Rewrites readable PDF objects using compressed object streams. If the rewrite is larger, the original file is returned and the result clearly reports no saving.
Steps to use this tool
- Select a readable PDF.
- Choose Compress PDF and wait for structural optimization.
- Compare the measured original and output sizes before downloading.
Tested example — 19 October 2026
The sample compares actual input and output bytes; its saving is specific to that fixture.
Selected sample: sample.pdf (2421 bytes, 2 pages).
Measured output: sample-optimized.pdf — 2421 bytes; 2 PDF pages.
This fixture remained at 2421 bytes with 0.00% saving; the tool returned the original because the rewrite was not smaller. Other PDFs can behave differently.
Test environment: Node + native canvas + actual site-ui.js form integration in LinkeDOM Representative sample; inspect your own output.
Check the result
Compare the reported byte sizes with the downloaded file properties. A result with no saving is valid when the original is already structurally optimized.
Files and privacy
The public tool processes selected documents in your browser. It does not send document bytes to a conversion server. The page and its bundled libraries still download from this website. Keep the original, use an up-to-date browser and inspect your output before sharing it. See the privacy policy for hosting and support information.
If processing fails
An encrypted or unreadable source cannot be optimized as an ordinary open PDF. If a scan stays large, adjust image resolution in the scanning app instead of expecting a stronger mode that this tool does not provide.
Implementation notes and sample evidence updated 2026-10-19. These notes describe the supported operation and its limits.
Check the local-processing claim in your browser’s Network panel.