Choose your PDF
The workspace shows the source filename and bytes and rejects files that cannot be read by the browser PDF parser.
Free online tool · no registration or login
Free PDF Compressor Online
Try a browser-based rewrite to reduce a PDF's size, then compare original and output bytes before downloading. Text-heavy files may shrink; image-heavy files may not.
- • Structural rewrite
- • Before/after bytes
- • Browser processing
- • Download when useful
PDF compressor workspace
Compare the rewrite before download
No registration or login required
Choose a PDF to compare its original and rewritten file sizes.
How to Compress a PDF
The comparison state is part of the workflow: keep a result only when the measured output is useful.
- Step 1
Choose your PDF
Select one PDF and review its filename, file size, and page count before processing.
- Step 2
Run the structural rewrite
Start the browser-side rewrite. This version focuses on compact PDF structure rather than rasterizing page content.
- Step 3
Compare and download
Keep the result only when the measured output is useful, then download it and open it in a PDF viewer.
How to Compress a PDF
Use the workspace to measure whether a rewritten PDF is actually smaller before you replace the original file.
Run the structural rewrite
The compressor creates a new PDF with compact object-stream settings. It does not pretend that every image stream can be recompressed.
Compare the output before download
Review original bytes, output bytes, page count, and the savings or unchanged warning before downloading.
What PDF Compression Can and Cannot Change
PDF files can contain text, vectors, fonts, images, metadata, and embedded resources. The result depends on which parts the browser library can rewrite.
Structure and object streams
The implementation uses pdf-lib save options intended to compact the document structure. Any byte reduction is measured from the actual result.
Scanned and image-heavy PDFs
A scanned document may remain large because its page images are not automatically replaced with lower-resolution images in this workflow.
When the output is not smaller
Keep the original if the output is equal or larger. The result state makes that outcome visible instead of claiming an unsupported reduction.
Privacy and Practical Limits
The page explains the browser boundary and the document cases that may need a desktop or specialized PDF engine.
Local browser processing
The page is built to read the selected PDF locally and does not require an account. Confirm network behavior independently for sensitive files.
Encrypted or damaged PDFs
Password-protected, damaged, or unusual PDFs may not load. The error state tells you to keep the original and try a compatible local viewer.
Large files and browser memory
Parsing and rewriting a large document can use significant browser memory. Practical limits vary by device and browser.
Privacy and limits
The selected PDF is read and rewritten in this browser. The page does not require registration or login; verify local handling in your browser when processing sensitive documents.
- This version attempts structural PDF compression and does not guarantee a smaller output for every file.
- It does not promise exact target sizes, raster image recompression, OCR, or preservation of every unusual PDF feature.
- Encrypted, damaged, very large, or unusual PDFs may fail to process in the browser.
PDF Compressor FAQ
Answers about reduction limits, browser processing, and when to keep the original file.
How does this PDF compressor work?
The browser reads the PDF with pdf-lib and writes a new document using compact object-stream settings. The result panel compares the source and output sizes.
Will compression always make my PDF smaller?
No. A PDF that is already optimized, image-heavy, encrypted, or structured in a way the browser library cannot rewrite efficiently may stay the same size or become larger. Keep the smaller result only when the comparison confirms it.
Can I compress a PDF to 1MB?
This version does not promise an exact target size. It attempts a structural rewrite and reports the measured result; image-heavy PDFs may require a different compression workflow.
Will text and vector content remain selectable?
The tool rewrites the PDF structure rather than rasterizing every page, but you should open the result and confirm important text, links, fonts, and vector content before relying on it.
Does this tool upload my PDF?
The compressor is designed to read and rewrite the selected PDF in this browser. No registration or login is required.
Can I compress encrypted or damaged PDFs?
Encrypted, damaged, or unusual PDFs may fail to load. The tool shows an error instead of producing a fictional completed result.
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