Compress PDF
Compress PDF files to reduce their file size for email or upload. Images drawn at more detail than a screen or printer can use are downsampled, text stays sharp, and the file never leaves your device.
- Input
- One PDF, including scans
- Output
- A smaller PDF, or your original if it can't shrink
- Runs
- In your browser. The file never leaves your device.
- Cost
- Free. No sign-up, no watermark.
How to compress a PDF
Choose your PDF
Open a PDF from your device. The file stays in your browser.
Pick a level
Balanced suits most documents and scans. Strong makes the smallest file for sharing on screen. Lossless changes no pixels.
Compare and download
See the original and new sizes and the percentage saved. If the result would be larger, you get your original file back.
Levels and size targets, and what each one changes
Scans actually shrink
Balanced downsamples images above 165 dpi and saves them as JPEG, which shrinks a typical 300 dpi scan to a fraction of its size. Strong goes to 100 dpi for files a fraction of the size.
Text is never touched
Only images are resampled. Text, vector drawings and fonts stay exactly as they were, so the document stays sharp and searchable.
Lossless when it must be
The lossless level resamples nothing: QPDF recompresses the file's streams and packs its objects, for files that must keep every pixel.
No limits or upload wait
Everything runs on your device, so there is no daily counter and nothing to upload. Very large files depend on your device's memory.
Frequently asked questions
How do I reduce the file size of a PDF?
Open the PDF here, keep Balanced or choose Strong for the smallest file, and download the result. You see the original and new sizes; if the file cannot get smaller, you get your original back.
How much smaller will my PDF get?
It depends on what the file holds. In our tests a three-page, 300 dpi scan went from 1.27 MB to 0.66 MB at Balanced (48% smaller) and to 0.15 MB at Strong (88% smaller); lossless compression could not shrink it at all. A PDF that is mostly text is already small and may shrink little at any level.
Will compression make my PDF blurry?
Balanced keeps images at up to 165 dpi, which looks sharp on screen and prints well for everyday documents. Strong uses 100 dpi, which is fine on screen but softer on paper. Lossless never changes an image.
Can I compress to a specific size?
Yes. Choose Under 1 MB, Under 200 KB or Under 100 KB, for upload forms with a size limit. The tool tries a few image quality and resolution settings and stops when the file is just under the limit, at about 90–95% of it, so images stay as sharp as the limit allows. It never goes over. If images alone cannot get it there, because most of the file is text, fonts or drawings, it tells you the smallest size it reached.
Which images are left alone?
Small images, images already at or below the target resolution that would not get meaningfully smaller, masks and a few special colour formats are kept exactly as they were.
Can I compress a password-protected file?
Yes, enter its opening password in the settings. To keep the file's encryption intact, a protected PDF gets lossless compression only; its images are not resampled.
Is my file uploaded anywhere?
No. Compress PDF runs entirely in your browser: the file is opened and processed on your own device and is never sent to our server. More in the privacy policy.
Is Compress PDF free to use?
Yes. Compress PDF is free, with no account to create and no software to install — open the page in a modern browser and start.