PureTools
Compress PDF Files, Free & Private
Reduce PDF file size entirely in your browser. Choose from four compression levels, from maximum to structure-only. No upload, no watermark, no quality loss on text.
Drop your PDF here
or · up to 100 MB
How to use the PDF Compressor
The PDF Compressor reduces file size by recompressing embedded images and cleaning up the internal file structure, all inside your browser. No account is needed, nothing is uploaded, and no watermark is added to the output. It works on desktop and mobile, and continues to function offline once the page has loaded.
- Select your PDF, drag and drop a file onto the upload area, or click Browse to open the file picker. Files up to 100 MB are accepted.
- Choose a compression level, Screen for maximum size reduction, eBook for a balanced result, Print for light compression, or Optimize for structural cleanup with no image changes.
- Click Compress PDF, the file is processed entirely in your browser. A progress bar tracks the operation, which typically completes in a few seconds.
- Download the result, the before and after file sizes are shown along with the percentage saved. Click the download button to save the compressed PDF. No watermark is added.
What each compression level does
Screen recompresses embedded JPEG photos at 35% quality, aggressive but often invisible on screen. Best for PDFs you share by email or upload to a web portal where file size limits apply. eBook uses 60% quality and is the recommended default for most files: meaningful size savings with no visible degradation on typical screens. Print uses 80% quality and makes only minor changes, suitable when the PDF must still look sharp on paper. Optimize skips image recompression entirely and focuses on structural work, removing unused objects, compressing internal streams and reorganizing the file, which is safe for every PDF regardless of content type.
Why PDF files can be compressed in the browser
A PDF file is a structured archive of objects: text streams, font definitions, vector paths and embedded images. The images in a PDF are often stored at a higher resolution or quality than the intended output requires. By re-encoding those images at a lower quality setting, using the same JPEG compression your browser already uses for web images, and by removing internal redundancy (duplicate objects, unused resources, uncompressed metadata streams), the tool can produce a substantially smaller file without touching text, fonts or vector content in any way. The process runs in a background thread so the page remains responsive throughout.
Frequently asked questions
Are my PDF files uploaded to a server?
No. Every PDF you select stays entirely on your device. The compression runs inside your browser using a JavaScript library called pdf-lib. No file data is ever sent to PureTools servers or any third party. You can disconnect from the internet after the page loads and the tool will still work perfectly, your files never leave your device. Your data is never used to train AI models or improve machine learning systems.
How much can my PDF be compressed?
The result depends on the content of your PDF. Files that contain high-resolution photos can shrink by 50–80% using the Screen or eBook levels. PDFs that consist mainly of text, vectors or line art typically see a 5–20% reduction from structural optimization alone, because there are no large images to recompress. The tool always shows you the exact before-and-after size so you can judge whether the result meets your needs.
What do the four compression levels mean?
Screen recompresses embedded JPEG images at 35% quality, the maximum reduction, best for PDFs viewed on screen where fine image detail is not critical. eBook uses 60% quality, giving a good balance between file size and visual clarity, ideal for sharing and reading on any device. Print uses 80% quality and makes only minor changes to images, suitable when you still need the file to look good in print. Optimize skips image changes entirely and applies structural cleanup only, removing unused objects, compressing internal data streams and linearizing the file, safe for any PDF and free of visual quality loss.
Will compression affect the quality of text or vector graphics?
No. Text, vector graphics, fonts and annotations are not modified by any compression level. Only embedded JPEG images are recompressed when using Screen, eBook or Print levels. Fonts remain fully searchable and selectable in the output. The Optimize level makes no changes to images at all. If your PDF contains no JPEG images, the output will be structurally cleaned but visually identical to the original.
Is there a file size limit?
Yes, each PDF must be 100 MB or smaller. This limit exists to protect your device memory and keep processing fast. The browser must hold the original and compressed versions in memory at the same time during processing. Most PDFs, including large reports, presentation exports and scanned documents, fall well under this limit. Data is cleared automatically when you close the tab, nothing is saved to your device by this tool.
Can I compress a password-protected PDF?
The tool will attempt to process password-protected PDFs that have permission restrictions (such as printing or copying limits) but no open password. If your PDF requires a password just to open it, the compression will fail with an error. In that case, remove the password with a dedicated PDF tool first, then return here to compress. PDFs that only restrict certain actions but can be opened without a password are handled automatically.
My PDF has no images, will it still get smaller?
Yes, a small reduction is still possible through structural cleanup. The tool removes unused internal objects, compresses data streams and reorganizes the file structure, a process that typically saves 5–15% on text-only PDFs. For the best result on a text-only file, choose the Optimize level, which focuses exclusively on this structural cleanup and skips image processing entirely. If you need to combine several smaller documents into one before compressing, the PDF Merger handles that step first.
Does the tool work offline?
Yes, after you have visited the page at least once. The tool is saved to your device automatically on the first visit. On all subsequent visits, even without an internet connection, the page loads instantly and compression runs entirely on your device. The library used for processing is also cached after your first visit, so the tool is fully self-contained offline. For the most reliable offline use, open the merger once while online, then keep the browser cache intact before using it without a connection.
Is my data erased when I close the tab?
Yes. Your chosen compression level is remembered only for the current browser session and cleared when you close the tab. The PDF file itself is held in your browser's memory only for the duration of the compression and is never written to your disk by this tool. No watermark is added to the output file. Closing the tab clears everything instantly, no trace of your file remains on the device.