Compress PDF
Reduce PDF file size by rasterizing pages at adjustable quality and resolution.
100% Private — Your files never leave your device. All processing happens in your browser.
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Result
How PDF Compression Works
This tool renders each page of your PDF as an image (using pdfjs-dist), then re-encodes each page as a JPEG and rebuilds the PDF (using pdf-lib). This lossy approach significantly reduces file size but text will no longer be selectable in the output.
Tips for Compressing PDF Files
- Start with medium compression — The medium quality setting offers the best balance between file size reduction and visual quality. For most documents, it reduces file size by 40–70% while keeping text sharp and images clear enough for on-screen viewing.
- Use high quality for print-ready PDFs — If the compressed PDF will be printed, use the high quality setting. Print documents need higher resolution images to avoid pixelation on paper, where imperfections are more noticeable than on screen.
- Use low quality for email-only documents — When the PDF is only for on-screen reading (email attachments, web downloads), the low quality setting provides maximum file size reduction. Text remains readable and images are clear enough for screen viewing.
- Compress after merging — If you merged multiple PDFs together, the combined file may be quite large. Run the merged result through the PDF compressor to optimize the final document size.
- Check the reduction percentage — The tool shows you the original and compressed file sizes along with the percentage reduction. If the savings are minimal, your PDF may already be optimized or contain mainly text (which compresses very little).
- Compress image-heavy PDFs for biggest savings — PDFs containing photographs or scanned documents benefit the most from compression. Text-only PDFs are already small and will see minimal size reduction.
When to Compress Your PDFs
- Email attachments — Most email providers limit attachments to 25 MB. Compressing a large PDF can bring it under the limit, saving you from having to use file-sharing services for simple document exchanges.
- Uploading to web portals — Many online forms, job applications, and government portals have strict file size limits (often 2–10 MB). PDF compression ensures your documents meet these requirements.
- Reducing storage costs — If you archive large numbers of PDFs (invoices, contracts, reports), compressing them can significantly reduce cloud storage usage and costs over time.
- Faster document sharing — Smaller PDFs download faster, open quicker, and are easier to share via messaging apps, collaboration tools, or slow internet connections.
- Optimizing scanned documents — Scanned PDFs are often 10–50 MB because they contain high-resolution images. Compression can reduce them to 1–5 MB while maintaining readable quality for archival purposes.
Frequently Asked Questions
Is the compression lossy?
Yes — each page is rasterized to a JPEG image. Text and vector graphics become images, so text is no longer selectable or searchable in the output PDF.
Is it safe?
Yes — your file never leaves your device. All compression happens locally in your browser.
Can I use this offline?
Yes — once the page is loaded, you can compress PDFs without an internet connection.
What quality setting should I choose?
Use high quality for documents you need to print or archive long-term. Medium quality is ideal for general sharing and on-screen reading. Low quality provides maximum compression for email attachments or temporary files where image sharpness is less critical.
Does compression affect text quality?
Text in native PDF documents (not scanned images) remains sharp and searchable after compression because it is stored as vector data, not pixels. Compression primarily reduces the size of embedded images. In scanned PDFs where text is part of an image, lower compression settings may slightly soften text appearance.
Can I compress scanned PDF documents?
Yes — scanned PDFs benefit the most from compression since they consist primarily of large images. A typical scanned document at 300 DPI can be reduced by 60–80% at medium quality while remaining perfectly readable. Use high quality if you need to preserve fine details for OCR processing.
Is there a file size limit for PDF compression?
There is no hard limit since compression runs entirely in your browser. However, very large PDFs (100+ MB) may be slow to process depending on your device's memory and processing power. For best performance on most devices, PDFs under 50 MB process smoothly.