About This Tool
Compress PDF reduces eligible files locally with qpdf WebAssembly. Low mode applies lossless structural and stream compression; Balanced and High can also recompress eligible raster images while preserving the PDF page structure.
What You Can Do
Three honest modes
Choose Low for lossless structural compression, Balanced for good image quality, or High for a smaller image-heavy result.
Measured savings
Compare the actual original size, compressed size, bytes saved, and percentage saved.
Local processing
The selected PDF is processed in the browser by the bundled qpdf engine.
How to Use
- 1
Choose one readable, unencrypted PDF up to 25 MB
Choose one readable, unencrypted PDF up to 25 MB.
- 2
Select Low, Balanced, or High compression and review the quality disclosure
Select Low, Balanced, or High compression and review the quality disclosure.
- 3
Start compression and wait for the measured result
Start compression and wait for the measured result.
- 4
Download the compressed PDF, then verify its pages and interactive features
Download the compressed PDF, then verify its pages and interactive features.
Practical Use Cases
Email and web delivery
Reduce an attachment before sharing it when the measured output is smaller.
Image-heavy reports
Recompress eligible photographs or scanned-page images with Balanced or High mode.
Document cleanup
Apply lossless stream and object compression to a text-and-vector PDF with Low mode.
Privacy and File Processing
Compress PDF keeps its PDF input in browser memory while the operation runs. The workflow creates Compressed PDF for local preview or download and does not send the entered values or selected file bytes to the GXA Toolbox application server.
Supported Inputs and Outputs
Input
Output
- Compressed PDF
How It Works
Compression is performed by the route-lazy qpdf WebAssembly worker using the selected stream, object-stream, and image-optimization preset, then the output is validated as a readable PDF.
Limitations and Important Notes
- A smaller output is not guaranteed for PDFs that are already efficient.
- Encrypted or password-protected files must be unlocked first.
- Any rewrite normally invalidates existing digital signatures.
- Balanced and High may change raster-image quality; forms, annotations, links, attachments, and specialized PDF features should be verified.
- The browser workflow is limited to 25 MB and does not downsample image pixel dimensions.
Worked Example
For an image-heavy report, compare Balanced and High results: High can produce a smaller file by using stronger JPEG recompression, while Low preserves image streams and only optimizes PDF structure.
Helpful Tips
- Keep the original until you inspect the compressed copy.
- Use Low for text, vector, or quality-sensitive documents.
- Try Balanced before High when photographs must remain clear.
- If the file is already optimized, accept the honest no-savings result instead of forcing a larger output.
Frequently Asked Questions
Is a smaller file guaranteed?
No. Results depend on the source, and the tool only offers a download when the output is genuinely smaller.
What is the difference between the modes?
Low is lossless structural compression. Balanced and High recompress eligible raster images, with High using stronger image compression.
Are image dimensions reduced?
No. Balanced and High change eligible image encoding quality but do not downsample pixel dimensions.
Will text stay selectable?
The PDF page structure is retained, so ordinary text remains text rather than being rasterized. Verify unusual or advanced documents after processing.
Are files uploaded?
The bundled qpdf WebAssembly engine processes the PDF locally in your browser.
Can I compress a signed PDF?
You can rewrite it, but doing so normally invalidates its digital signature. Keep the signed original.