Compress PDF
Reduce PDF file size while maintaining quality. Choose your compression level, preview the result, and download instantly. All processing happens in your browser.
What Is PDF Compression?
PDF compression reduces the file size of a PDF document by re-encoding its content at a lower resolution or quality setting. Large PDFs are common when documents contain high-resolution scans, embedded photographs, or complex vector graphics. Email providers, upload forms, and cloud storage services often impose file size limits that make sharing uncompressed PDFs difficult or impossible.
This free online PDF compressor works entirely in your browser. Your files are never uploaded to any server, making it safe for confidential contracts, financial statements, medical records, and any other sensitive documents. The tool re-renders each page as a compressed JPEG image at your chosen quality level, then reassembles the pages into a new, smaller PDF.
How to Compress a PDF
- Upload your PDF. Drag and drop a file onto the upload area, or click to browse your device. Files up to 100 MB are supported.
- Choose a compression level. Select Low (best quality, smaller reduction), Medium (balanced), or High (smallest file, some quality loss). The description updates to explain each option.
- Set your output filename. Edit the filename field to give your compressed PDF a meaningful name before downloading.
- Click "Compress PDF" (or press Ctrl+Enter). The progress bar shows real-time status as each page is processed.
- Review the results. Compare original and compressed sizes, check the reduction percentage, and scroll through the preview to verify quality.
- Download. Click "Download Compressed PDF" (or press Ctrl+D) to save the smaller file to your device.
Features
- Three compression levels. Fine-tune the balance between file size and visual quality.
- Real-time progress. A progress bar and page counter show exactly where the tool is in the compression process.
- Size comparison stats. See original size, compressed size, percentage reduced, and processing time at a glance.
- Full preview. Scroll through up to 20 pages of the compressed result before downloading.
- Custom filename. Name your output file before downloading instead of accepting a generic suffix.
- Keyboard shortcuts. Ctrl+Enter to compress, Ctrl+D to download.
- Error handling. Friendly messages for wrong file types, oversized files, or processing failures.
- 100% private. No server upload. Your PDF never leaves your browser.
- Works offline. Once loaded, the tool functions without an internet connection.
Compression Levels Explained
Low compression renders pages at 95% scale with 90% JPEG quality. Text remains crisp and images look nearly identical to the original. Expect a 10 to 30 percent size reduction. Best for documents you plan to print or archive at high quality.
Medium compression uses 80% scale and 72% JPEG quality. This is the default and works well for most use cases: email attachments, form submissions, and general sharing. Typical reduction is 40 to 60 percent.
High compression drops to 60% scale and 50% JPEG quality. The file size shrinks dramatically (often 60 to 80 percent), but images may show visible artifacts. Use this when file size matters more than visual fidelity, such as uploading to systems with strict size limits.
Common Use Cases
Email attachments. Most email providers cap attachments at 25 MB. A scanned multi-page document can easily exceed that. Compress it to medium quality and it will typically fit within the limit while remaining readable.
Web upload forms. Job applications, insurance claims, and government portals often restrict uploads to 5 or 10 MB. High compression can shrink a 30 MB scan down to under 5 MB. If you also need to remove sensitive information first, use our Redact PDF tool before compressing.
Cloud storage savings. Compressing archived PDFs frees up space on Google Drive, Dropbox, or OneDrive. A folder of scanned receipts can shrink by 50 percent or more without losing legibility.
Tips and Tricks
- Start with Medium. If the result is too large, re-upload and try High. If quality is poor, try Low. Medium works for 80% of use cases.
- Remove unnecessary pages first. Use Delete PDF Pages to strip blank or irrelevant pages before compressing. Fewer pages means a smaller file regardless of compression level.
- Check the preview. Always scroll through the compressed preview before downloading. Text-heavy documents compress well at any level, but photo-heavy pages may need Low compression to stay sharp.
- Combine with other optimizations. If your PDF has unnecessary metadata or form fields, use PDF Metadata Editor to strip extra data before compressing.
- Keyboard workflow. On desktop, press Ctrl+Enter to start compression and Ctrl+D to download without reaching for the mouse.
Frequently Asked Questions
Does compression reduce text quality?
The tool re-renders pages as JPEG images, so text is rasterized. At Low and Medium settings, text remains sharp and readable. At High compression, very small text may show slight softening. For text-only PDFs, even High compression produces readable results.
Is my PDF uploaded to a server?
No. The entire compression process runs locally in your browser using JavaScript. Your file never leaves your device, making this tool safe for confidential documents.
What is the maximum file size?
The tool supports PDF files up to 100 MB. Since processing happens in your browser, performance depends on your device. Most files under 30 MB compress in under 10 seconds.
Can I compress a password-protected PDF?
No. Protected PDFs must be unlocked first. Use our Unlock PDF tool to remove the password, then upload the unlocked file here to compress it.
Will the compressed PDF still be searchable?
Since compression converts pages to images, the text layer is removed. If you need searchable text after compression, run the compressed file through our OCR PDF tool to add a text layer back.
How much smaller will my PDF get?
Results vary by content. Image-heavy scanned documents typically shrink 50 to 80 percent. Text-heavy documents with few images may only shrink 20 to 40 percent. The tool shows exact before and after sizes so you can decide if the reduction is sufficient.
Related Tools
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Conclusion
Shrinking a PDF should not require uploading sensitive files to unknown servers or paying for desktop software. This free browser-based compressor gives you three quality levels, real-time progress feedback, a full preview of the result, and exact size statistics. Whether you need to fit a scan under an email attachment limit, meet a portal upload restriction, or simply save storage space, the entire process takes seconds and keeps your documents completely private. Drop a PDF above to get started, or explore our other free PDF tools for more document editing capabilities.