Compress & Optimize PDF
A privacy-first, in-browser PDF optimizer. It rebuilds your PDF efficiently and reports the size change — honestly, with no uploads.
Your PDF is optimized in your browser — nothing is uploaded.
Click to choose a PDF or drag and drop it here
We optimize it locally and show the before/after size
What this tool does — and what it does not
Let us be clear, because many sites overpromise here. This tool performs a lossless re-save of your PDF in your browser using the open-source pdf-lib library, writing the document with object streams for a more compact file structure. For some PDFs — especially those exported by older or inefficient software — this can meaningfully reduce the file size with zero loss of quality. For PDFs that are already optimized, or whose size comes mainly from high-resolution images, the savings will be small or none.
What this tool deliberately does not do is aggressively re-compress or downscale the images inside your PDF. True image recompression generally requires server-side processing and uploading your file, which would defeat the privacy promise of this site. We would rather give you an honest, safe optimization than claim dramatic compression we cannot deliver locally.
How to optimize a PDF
- Click the box above or drag a PDF onto it.
- Click Optimize PDF.
- The tool rebuilds the file in your browser and shows the original and new sizes.
- The optimized
optimized.pdfis downloaded automatically. - If the result is not smaller, simply keep your original file.
Why use a privacy-first optimizer
PDFs frequently hold sensitive material — contracts, statements, scans of identity documents. Sending those to a remote compression service means trusting an unknown server with your data. This optimizer never uploads your file: the entire process happens on your device, no account is required, and nothing is stored. It is a sensible first step to try before resorting to a heavier server-side tool, particularly when the document is confidential.
Related tools
New here? Read how to merge pdfs without losing quality or browse all our PDF guides.
Frequently asked questions
How much smaller will my PDF get?
It depends entirely on the file. PDFs that contain redundant data or are inefficiently structured may shrink noticeably; well-optimized or image-heavy PDFs may shrink only slightly or not at all. We always show the before-and-after size so you can decide whether to keep the result.
Does this re-compress the images inside my PDF?
No, and we want to be upfront about that. This tool rebuilds the PDF structure efficiently but does not downscale or re-encode embedded images. If your PDF is large because of high-resolution photos, the savings here will be modest.
Is my file uploaded anywhere?
No. The optimization runs entirely in your browser using the open-source pdf-lib library. Your PDF never leaves your device.
Will the quality of my document change?
No. Because images and text are not re-compressed, the visual quality of your document is preserved exactly. This is a lossless re-save.
Why did my file get slightly larger?
On rare occasions a re-saved PDF can be marginally larger if the original was already highly optimized. We show the resulting size and only suggest keeping the new file when it is actually smaller.
What if I need aggressive compression?
For heavy reduction of image-heavy PDFs you generally need server-side tools that re-encode images, which would require uploading your file. This privacy-first tool deliberately avoids that and focuses on safe, local optimization.