PDF Compressor
Rewrite PDF structure to reduce some unoptimized files.
Rewrite a PDF with object streams entirely in your browser. This does not resample images, so some PDFs may not become smaller.
Tool area
What PDF Compressor does
PDF Compressor rewrites PDF structure in your browser and attempts to reduce the size of unoptimized files. It is useful for PDFs created by older tools or documents with extra structural overhead.
This tool does not resample images and cannot guarantee that every PDF becomes smaller. Compare original and output size before downloading.
When to use PDF Compressor
Use it when a PDF is too large for upload or email, or when you want to try browser-side optimization before sharing.
- A resume, form, or application PDF is over an upload limit
- A PDF created by older software is larger than expected
- You want to reduce an attachment before emailing it
- You prefer local processing instead of uploading a private PDF
Step-by-step usage guide
1. Choose a PDF under 40 MB.
2. Select Compress PDF and wait for the rewrite.
3. Compare original size, output size, and size change.
4. Download the result only if it is smaller and opens correctly; otherwise keep the original.
Tips and best practices
PDF structure optimization is different from image compression, so results depend heavily on the file.
- Open the output and check pages and text before using it
- Image-heavy or already optimized PDFs may not shrink
- Password-protected or restricted PDFs may not process
- Use a dedicated image-resampling PDF tool if you need to lower image resolution
How to use
- Choose a PDF under 40 MB.
- Compress and wait for the rewrite.
- Compare the result before downloading.
Use cases
- Optimize PDFs created by older tools.
- Reduce some structural overhead.
Who is it for
- Users testing structural optimization on unoptimized PDFs
- Document managers comparing file size before and after rewriting
- Professionals who need files to remain in the browser
Real examples
Test a PDF created by older software
Keep the original, rewrite the PDF structure, and compare sizes. Even when output is smaller, reopen it and inspect fonts, pages, forms, and attachments. Keep the original whenever the result is not smaller.
Decide whether image compression is actually needed
A scan-heavy PDF may not shrink because image streams dominate its size. That requires a separate image-resolution decision; this tool deliberately avoids resampling images and therefore cannot promise a compression ratio.
Good to know
- A smaller output does not imply lower visual quality because this tool primarily reorganizes objects and streams.
- Encryption, signatures, complex forms, and unusual attachments may not survive rewriting and require careful verification.
- Do not replace legal, signed, or archival originals until the rewritten file has been fully compared.
FAQ
- Is the PDF uploaded?
- All input and files are processed only in this browser tab and are not uploaded to a server.
- Are encrypted PDFs supported?
- PDFs that require passwords or restrict modification are not supported.
- Why did the file not become smaller?
- The tool does not lower image resolution, so optimized or image-heavy PDFs may not shrink.
Privacy & local processing
🔒 This tool runs entirely in your browser. No data is uploaded to any server.
All input and files are processed only in this browser tab and are not uploaded to a server.
Trust & usage note
This tool runs mainly in your browser. Your input is not actively uploaded to a server. Avoid entering highly sensitive data. Results are for reference only.
Disclaimer
This tool performs structural PDF optimization only; it does not resample images or guarantee a compression ratio.
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