Compress PDF
Reduce file size while keeping maximum quality
How it works
Upload your file
We process it instantly in your browser
Download your result in one click
Your files stay private. All processing happens locally in your browser. Files are never uploaded to any server.
How to Use Compress PDF
Large PDFs slow down email, fail to upload to portals, and eat up storage. PDF Mate's compression tool reduces file size by optimizing embedded images and removing redundant metadata — all inside your browser, without sending your file to any server.
- 1
Upload your PDF
Click "Select File" or drag your PDF into the upload area. The tool accepts any PDF regardless of how it was created.
- 2
Choose a compression level
Select Standard (balanced quality and size) or Strong (smallest file, slight image softening). Standard is best for most documents. Strong works well for scanned pages shared by email.
- 3
Click "Compress PDF"
The compression runs locally in your browser via WebAssembly. No file leaves your device. A progress bar shows how far along the process is.
- 4
Review the size reduction
The tool displays the original and compressed file sizes so you can see exactly how much space you saved before downloading.
- 5
Download the compressed PDF
Click "Download" to save the compressed file. Open it and check a few pages to confirm the quality meets your needs.
Pro Tips
- ✓PDFs with many high-resolution photos compress the most — sometimes 70–85% smaller.
- ✓Text-only PDFs are already quite compact; typical reduction is 10–30%.
- ✓If you need the file under a specific size limit (e.g., 5 MB for an email attachment), try Strong compression first.
- ✓Never compress a PDF you intend to print at large format — compression reduces image DPI and may cause visible softening at print sizes above A4.
- ✓For repeated compressions, always start from the original file. Re-compressing a compressed PDF yields diminishing returns and can degrade quality further.
Compression is non-destructive to your original file. The compressed version is a separate download — your source PDF remains untouched.
Frequently Asked Questions
How much can I reduce a PDF file size?
It depends on the content. PDFs with high-resolution images can be reduced by 70–85%. Text-heavy PDFs typically compress by 20–40%. The tool shows you the output size before you download.
Will compression reduce the quality of my PDF?
Standard compression keeps images sharp enough for screen reading and everyday printing. Strong compression may slightly soften images but produces the smallest files — ideal for email attachments.
What is the maximum file size I can compress?
PDF Mate runs entirely in your browser, so the limit depends on your device memory. Files up to several hundred MB typically work fine on modern devices.
Can I compress a PDF that is already compressed?
Yes, but the additional reduction will be smaller. If a PDF has already been compressed, further compression may yield only a 5–15% reduction.
Does the compressed PDF look different when printed?
For Standard compression, printed output is virtually identical. For Strong compression, very high-resolution images may appear slightly less sharp when printed at large sizes.
Why is my PDF not getting smaller?
Some PDFs are already optimized — particularly those created from vector-based sources like InDesign or Word without embedded high-res images. In these cases, additional compression has little effect.
Is it safe to compress confidential documents here?
Yes. All processing happens inside your browser using WebAssembly. Nothing is transmitted to any server. Your file never leaves your device.