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  1. Toolkernel
  2. /
  3. PDF Tools
  4. /
  5. Compress

Compress PDF Online

Reduce PDF file size while maintaining quality

Your files never leave your device

Drop PDF file here

or click to browse your computer

Choose File
Max 50MB per file

How to Compress a PDF File

  1. 1
    Upload Your PDF
    Drag and drop your PDF file or click to browse. Processing happens locally in your browser.
  2. 2
    Choose Compression Level
    Select High Quality for printing, Balanced for general use, or Maximum Compression for smallest size.
  3. 3
    Compress & Download
    Click "Compress PDF" and see the before/after size comparison. Download your optimized file.

Why Compress PDF Files?

Large PDF files are cumbersome to share via email, upload to websites, or store in cloud services with limited space. Compression reduces file size dramatically while maintaining document usability.

Email services typically limit attachments to 10-25MB. PDF compression ensures your documents stay under these limits without splitting files or using file-sharing services. Faster uploads and downloads also save time, especially on slower connections.

For web applications, smaller PDFs load faster, improving user experience. Document management systems and digital archives also benefit from reduced storage costs when files are properly optimized.

Compression Quality Levels

High Quality

Minimal compression, best quality

  • • Best for printing
  • • Maintains image clarity
  • • ~10-30% size reduction

Balanced

Good balance of size and quality

  • • Ideal for sharing
  • • Good readability
  • • ~30-50% size reduction

Maximum Compression

Smallest file size possible

  • • Best for email
  • • Web uploads
  • • ~50-80% size reduction

Compression Tips

Image-heavy PDFs compress best. Scanned documents and photo-rich files can see 50-80% reduction.

Text-only PDFs are already efficient. Expect smaller reductions (10-20%) for documents without images.

Already compressed PDFs may not shrink much further. The best results come from unoptimized files.

Email attachments often have 25MB limits. Use Maximum Compression for files you need to send via email.

Common Use Cases

Email Attachments

Reduce file size to fit within email size limits (typically 10-25MB).

Web Uploads

Optimize PDFs for website uploads where smaller files load faster.

Cloud Storage

Save storage space by compressing archived documents.

Mobile Sharing

Create smaller files that transfer faster over mobile networks.

Form Submissions

Meet file size requirements for online applications and forms.

Document Archives

Reduce storage costs by compressing large document collections.

Frequently Asked Questions

How much will my PDF file shrink?

Compression varies by content. Image-heavy PDFs can shrink 40-80%. Text documents may only reduce 10-20% as they're already efficient.

Will compression make my PDF unreadable?

No. Even Maximum Compression keeps text sharp and readable. Images may show some quality loss at highest compression, but documents remain usable.

Which quality level should I choose?

Use High Quality for documents you'll print, Balanced for general sharing, and Maximum Compression for email attachments or size-restricted uploads.

Can I compress a PDF that's already been compressed?

Yes, but you may see minimal additional reduction. Already-optimized PDFs don't compress much further.

Is my PDF uploaded to a server?

No. All compression happens locally in your browser. Your file never leaves your device.

Related PDF Tools

Merge PDF

Combine multiple PDFs into one

Split PDF

Extract specific pages

Organize Pages

Reorder, rotate, delete pages