Free · Open source · No upload
Get any file to the exact size you need.
Compress, convert and sign PDFs and photos in your browser. Your files are never uploaded.
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How it works
Choose a file
Select or drop a PDF or photo into the workspace.
Set your target
Pick an exact size limit or strength goal.
Download
Get your file instantly without leaving your browser.
Questions
Are my files sent to any server?
Is Weesize really completely free?
How does exact-size compression work?
Does it work offline?
Compress a PDF on Windows
Get any file to the size you need. Privately.
1 Open this page on that device and wait until the tools are on-device.2 Add the PDF from local files and compress. A size page can set a goal if you need one.3 Save the download with the system sheet. That sheet is the operating system, not an upload by this app.
About this tool
Open the page in the browser you already use and drop the PDF. No store install is required. A managed browser may log addresses you visit. It does not receive the PDF body from this app, because the app does not send that body.
Compress a PDF on Windows stays on this device. The download is the copy you keep, and Weesize does not store a second one. Close the tab when you are finished and the bytes are gone.
- No upload: the same page runs on the phone or the computer, so you do not switch to a server tool per device.
- Speed: the file does not travel to a server and back, so the wait is only the work itself.
- Quality: the original is kept when the new file would be worse or is not actually smaller.
FAQ
Does “Compress a PDF on Windows” upload my file?
Compress a PDF on Windows reads the file in this tab. There is no upload step and no account.
What will “Compress a PDF on Windows” actually change?
Compress a PDF on Windows does not post the PDF. A later share-sheet action is the operating system, and you can see it.
When is “Compress a PDF on Windows” the wrong job?
For Compress a PDF on Windows, do not switch to a store app that demands an account before it will shrink the same file.
How do I check the result of “Compress a PDF on Windows”?
After Compress a PDF on Windows, read a page on the device, then try airplane mode for a second compress once the page is ready.
Can I run “Compress a PDF on Windows” with Wi-Fi off?
Load this page, then turn Wi-Fi off and run Compress a PDF on Windows again. A finished result is the proof that the file was not sent anywhere.
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Last updated 2026-09-27.