Compress PDF Online Free
Compress image-heavy and scanned PDFs with three quality levels. Processing stays in your browser, with no upload, signup, or watermark.
No PDF selected yet. Add one PDF to reduce its file size.
Compression quality
Lower quality usually creates a smaller PDF. Results depend on the original document.
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How to compress a PDF online
- Choose one PDF. The file is read directly in your browser and is never uploaded to PDF2atom.
- Select a compression quality. Smaller file uses more aggressive page resampling, Balanced suits most documents, and Higher quality keeps pages sharper.
- Compress and compare. Download the rebuilt PDF after checking the original and final file sizes.
How this PDF compressor reduces file size
This tool renders each PDF page as a compressed image and then rebuilds a new PDF. That approach is useful for scanned documents, photo-heavy reports, receipts, forms, and image-based PDFs that contain more visual detail than necessary. The result often becomes much smaller because oversized page images are resampled and saved at a controlled quality.
Compression results vary. A scanned PDF can shrink substantially, while a small text-only PDF may stay similar in size or even become larger. The result summary tells you what happened, so you can try another quality level before downloading.
Important tradeoffs before compressing
Because every page is rebuilt as an image, selectable text, hyperlinks, form fields, annotations, signatures, bookmarks, and document layers are flattened. Use this compressor when sharing and file size matter more than keeping interactive PDF features. Keep the original file if you may need to edit, search, copy text, or fill forms later.
Common use cases
- Reduce scanned paperwork before attaching it to an email.
- Prepare receipts, forms, school records, or application documents for an upload portal.
- Create a lighter copy of a photo-heavy PDF for mobile viewing or archiving.
- Shrink a PDF before using Merge PDF to combine several documents.
Compress a PDF on Mac with clearer quality choices
Mac Preview includes an export workflow for reducing PDF file size, but a browser tool can be more convenient when you want the compression choices explained before processing. Use Smaller file for a strict upload limit, Balanced for everyday sharing, or Higher quality when fine details matter. Open the downloaded result in Preview and compare it with the original before sending or submitting it.
For a Mac-focused walkthrough and quality checklist, use Compress PDF on Mac. Both pages process the document locally in your browser and do not upload it to PDF2atom.
Privacy & Security
Your PDF stays in your browser. PDF.js renders pages locally and pdf-lib rebuilds the result on your device. PDF2atom does not upload, store, inspect, or analyze your document.
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Frequently asked questions
Are my files uploaded when I compress a PDF?
No. PDF.js reads and renders the document inside your browser, and pdf-lib creates the compressed result locally. PDF2atom does not receive or store your PDF.
Why did my compressed PDF become larger?
Small text-only PDFs may already be efficiently encoded. Rebuilding every page as an image can make those files larger. Try the smaller-file setting, or keep the original when the result does not improve.
Will selectable text and form fields still work?
No. This compression method flattens every page into an image. Text selection, links, forms, annotations, layers, and other interactive features will not remain interactive.
Which compression setting should I choose?
Balanced is a useful starting point. Choose Smaller file for strict upload limits or email attachments, and Higher quality when page sharpness matters more than maximum reduction.
Does it work with password-protected PDFs?
Fully password-locked PDFs need to be unlocked first using the password you know. PDF2atom does not bypass, crack, or remove passwords without authorization.
What file size works best?
The practical limit depends on your browser memory and page count. For stable processing, start with PDFs under 50 MB and close memory-heavy tabs before compressing large documents.
Can I compress a PDF on a Mac without installing another app?
Yes. Open this page in a modern Mac browser, choose a quality setting, compress the PDF locally, and review the downloaded result in Preview.