Compress a PDF file for upload limits
Reduce PDF file size while maintaining quality. Free online PDF compressor for smaller files.
Fast answer
Use Compress PDF when the main problem is file size and you need a smaller PDF that is easier to upload, email, or store.
What this tool is best for
- Reducing PDF size for government, school, or job portal upload limits.
- Shrinking scanned PDFs before email or messaging.
- Making large PDFs load faster on slower connections.
Inputs and outputs
Inputs
- A PDF file that needs size reduction.
- Optional compression preference depending on the tool flow.
Outputs
- A smaller PDF file.
- Optimized document assets where possible.
About This Tool
Compress PDF reduces the file size of your PDF documents while maintaining acceptable quality. This is essential for email attachments, web uploads, or saving storage space.
The tool offers multiple compression levels to balance between file size reduction and quality preservation. You can choose aggressive compression for maximum size reduction or light compression to maintain higher quality.
All compression happens in your browser, ensuring your documents never leave your device.
Practical guide for this tool
Use Compress PDF when the main problem is file size and you need a smaller PDF that is easier to upload, email, or store.
What this tool does
- Reduces PDF size by optimizing document data and images where the file allows it.
- Helps with email attachments, upload portals, slower connections, and storage limits.
- Keeps the original document structure visible, but stronger compression can reduce image quality.
When to use it
- Reducing PDF size for government, school, or job portal upload limits.
- Shrinking scanned PDFs before email or messaging.
- Making large PDFs load faster on slower connections.
Practical examples
- Make a portal-friendly upload: start with portfolio.pdf at 18 MB and check that the output matches portfolio-compressed.pdf under the portal limit.
- Shrink a scanned handout: start with scan.pdf and check that the output matches scan-smaller.pdf.
Privacy and file handling
- Use this tool only on documents you own or have permission to process.
- OpenToolsKit is designed around browser-side processing where applicable, but you should still inspect the downloaded result before sharing it.
- Keep the original file until the output has been opened and verified.
Common mistakes to avoid
- Trying to force an exact target size when the PDF content cannot shrink that far without quality loss.
- Compressing a damaged PDF before repairing it.
- Sending the compressed file without checking signatures, small text, and scanned pages at normal zoom.
Troubleshooting
- If the file barely shrinks, it may already be optimized or mostly text-based.
- If pages become hard to read, use a lighter compression setting or remove unnecessary pages instead.
How to Use
Upload Your PDF
Drag and drop your PDF file or click to select the document you want to compress.
Choose Compression Level
Select your preferred compression level: Low (best quality), Medium (balanced), or High (smallest size).
Compress and Download
Click Compress to reduce the file size, then download your optimized PDF.
Use Cases
Email Attachments
Reduce PDF size to meet email attachment limits and ensure faster delivery.
Web Publishing
Optimize PDFs for web download to improve page load times and user experience.
Storage Optimization
Compress archived documents to save disk space while maintaining accessibility.
When to use this instead of a related tool
Repair PDF
Use this adjacent tool when the job moves beyond compress pdf into a related PDF workflow.
Compare with Repair PDFLimitations and edge cases
- Compression cannot guarantee an exact target size. Use a more specific upload-fix tool when exact KB control matters.
- This tool does not repair corruption. Use Repair PDF if the file is broken.
Examples
Make a portal-friendly upload
Input
portfolio.pdf at 18 MB
Output
portfolio-compressed.pdf under the portal limit
Shrink a scanned handout
Input
scan.pdf
Output
scan-smaller.pdf
Task pathways
Where this fits in pdf workflows
Optimize and repair PDFs hub
Choose the closest task in this PDF category before switching tools.
Go to Optimize and repair PDFs hubBuild a multi-step PDF workflow
Chain adjacent PDF actions when one tool is only part of the job.
Go to Build a multi-step PDF workflowBrowse all browser PDF tools
Scan every live PDF utility and route to the right next action.
Go to Browse all browser PDF toolsFrequently Asked Questions
How much can I reduce the file size?
Compression results vary based on the PDF content. Image-heavy PDFs can often be reduced by 50-80%, while text-only PDFs may see smaller reductions.
Will compression affect text quality?
Text remains sharp and readable at all compression levels. Only images and graphics are affected by compression.
Can I compress multiple PDFs at once?
Yes, you can upload and compress up to 10 PDF files simultaneously.
Can PDF compression guarantee a specific file size?
No. The final size depends on images, fonts, page objects, and how the source PDF was created. Compress again only if readability remains acceptable.
What should I check before sharing output from Compress PDF?
Open the downloaded file and verify page order, readability, visible edits, and any privacy-sensitive details before sending or filing it.
Does Compress PDF upload my document to OpenToolsKit servers?
OpenToolsKit is designed around browser-side processing where applicable. Some browser features, third-party links, or unsupported file types can have different boundaries, so review the privacy page for details.
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