Compress PDF
Shrink your PDF, privately in your browser.
How to compress a PDF
- 1
Add your PDF
Drop or select the PDF you want to shrink.
- 2
Pick a level
Light keeps text selectable; stronger levels rasterize for smaller files.
- 3
Compress & download
See the size saved and download, all on your device.
Why compress PDFs in your browser?
Email attachment limits shouldn’t force you to upload a private document to a compression service. PDFMergely shrinks your PDF locally, the smaller file is produced on your device and nothing is sent anywhere.
Aiming at an exact size?
Most compression jobs are really about hitting one specific number: 100 KB for a portal, or 25 MB so email will send it. We wrote up how to reach an exact size without wrecking the document, and why the work should happen on your device: read the compression guide.
Do this from your toolbar. The free PDFMergely browser extension compresses PDFs without opening a tab, and it runs entirely on your device: no permissions, no uploads, and it works offline. Get the extension.
Frequently asked questions
Is my file uploaded?+
No. Compression runs entirely in your browser. Your PDF is never uploaded.
Will the quality drop?+
Light mode is lossless and keeps text selectable. Stronger levels rasterize pages to images for bigger savings, which reduces sharpness and makes text non-selectable.
How much smaller will it get?+
It depends on the file. Image-heavy and scanned PDFs shrink the most with the stronger levels.
Can I compress a PDF to a specific size, like under 1 MB or a set number of KB?+
Yes. Switch to Target size mode, type the size you need in KB or MB, and PDFMergely compresses toward it, lowering image quality as needed and rasterizing pages if the target is small. It all runs in your browser, so even a size-limited file is never uploaded.
How do I make a PDF small enough to email?+
Use Target size mode and enter a limit that fits your mail provider, for example under 10 MB, or a few hundred KB for a stricter inbox. The file is compressed on your device to fit that size.
Can I convert a PDF from KB to MB, or MB to KB?+
There is nothing to convert: KB and MB are just units of the same file size (1 MB is 1024 KB). If a PDF is too large, shrink it with Target size mode; if it is already small, it is fine as it is.
Is it free?+
Yes, compressing PDFs is completely free with no sign-up.
Common uses
Task-specific guides for the situations people reach for this tool for.