Private PDF Compressor with Image Optimization
Last Verified Stable: December 2025 Updated Engine: Now features advanced image downsampling and metadata stripping for maximum file reduction.
Why Browser-Based Compression is the 2025 Security Standard
Most "online" compressors force you to upload sensitive data to their servers. Fileverter uses WebAssembly (WASM) to process your files entirely within your own browser. Your files never leave your device.
Advanced Image Optimization Technology
What makes our tool different? Most PDFs are large because they contain high-resolution images. Our engine specifically targets these elements:
- Intelligent Downsampling: We reduce the DPI (Dots Per Inch) of images to a web-friendly 72-150 DPI.
- Image Re-compression: We use advanced DCT (Discrete Cosine Transform) algorithms to shrink image data without visible blurring.
- Metadata Stripping: We remove "invisible" data attached to images (like camera info or location) that adds unnecessary weight to your PDF.
Three Intelligent Compression Modes
| Mode | Target Reduction | Best Use Case | Image Quality |
|---|---|---|---|
| Light | 20-40% | Resumes & Portfolios | 100% Original |
| Balanced | 50-70% | Email Attachments | High (300 DPI) |
| Maximum | Up to 90% | Web Uploads & Mobile | Optimized (72 DPI) |
Light Compression (High Fidelity)
Best for: Documents where visual clarity is the #1 priority.
- Preserves high-resolution images for printing.
- Ideal for compressing PDF for email without any noticeable quality loss.
Balanced Compression (The "Sweet Spot")
Best for: Daily office tasks and standard document sharing.
- Optimizes images for screen viewing while maintaining professional sharpness.
- Greatly reduces PDF file size for online sharing.
Maximum Compression (Extreme Shrink)
Best for: Strict portal limits and archiving.
- Aggressively compresses images to shrink large PDF files to 1MB or less.
- Perfect for making PDF files smaller for WhatsApp or slow internet connections.
Key Features of Our 2025 Utility Engine
- Zero-Server Architecture: Your data is 100% secure. Everything happens on your CPU.
- Lossless Text Preservation: While we optimize images, we keep your text as "vectors," meaning it remains perfectly crisp and searchable at any zoom level.
- No Watermarks: Create clean, professional documents with no branding.
- Multi-Device Ready: Works on Windows, Mac, iOS, and Android without an app install.
How to Compress Your PDF in 3 Seconds
- Select Your PDF: Drag and drop your file into the secure box above.
- Choose Your Mode: Select Light, Balanced, or Maximum.
- Download Locally: Save your optimized file instantly.
Frequently Asked Questions
Does this tool work for scanned PDFs? Yes! Scanned PDFs are essentially just large images. Our tool is highly effective at shrinking these by optimizing the image layers inside the file.
Will I lose text quality? No. Our engine is designed to compress images in PDF while leaving the text characters (fonts) untouched. Your document will remain fully readable and searchable.
Is there a file limit? Since the processing happens on your device, the speed depends on your computer's power rather than your internet speed.
2025 Pro-Tip for Best Results
If you have a PDF that is still too large after compression, try "Flattening" the file first. This merges all layers and annotations into a single layer, allowing our image optimization engine to work even more efficiently.