🗜 Compress PDF Online — Reduce PDF File Size

Reduce PDF file size by re-rendering pages at lower quality. Runs entirely in your browser.

ℹ️ How it works: Each page is rendered to a canvas via PDF.js at the selected scale/quality, then re-embedded as JPEG images in a new PDF using PDF-lib. Text-only PDFs may already be small — this tool is most effective on image-heavy PDFs.
📂 Select PDF File
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Drop PDF file here

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⚙️ Compression Settings
💡 Tips for Better Compression

What is the PDF Compressor?

The PDF Compressor is a free, browser-based tool that reduces the file size of PDF documents by re-rendering each page at a lower resolution and re-encoding it as a compressed JPEG image embedded in a new PDF. This approach is most effective on PDFs that contain high-resolution images, scanned documents, or photo-heavy pages. By choosing a compression level from High to Low, you can balance file size against visual quality to suit your needs — whether that means a small file for email attachments, or a larger high-fidelity file for archival purposes.

Email providers typically cap attachments at 10–25 MB, cloud storage costs money, and large PDFs are slow to load on mobile devices. The PDF Compressor can dramatically reduce file sizes for image-heavy documents, often achieving 40–70% reduction. For text-only PDFs with no embedded images, compression gains are minimal since there is no image data to re-encode.

How to Use — Step-by-Step

  1. Upload your PDF file by clicking the drop zone or dragging it onto the page.
  2. Select a compression level: High (smallest file), Medium (balanced), Low (best quality), or Custom.
  3. For Custom mode, adjust the JPEG quality percentage and render scale independently.
  4. Click Compress PDF — a progress bar shows each page being processed.
  5. Review the results showing original size, compressed size, and percentage saved.
  6. Click Download Compressed PDF to save the smaller file to your device.

Key Features & Benefits

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Three Compression Presets

High, Medium, and Low presets let you quickly choose between maximum compression and maximum quality.

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Custom Quality Control

Fine-tune JPEG quality from 10–100% and render scale from 0.4× to 2× for precise control over output quality.

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Size Reduction Stats

Displays before/after file sizes and the exact percentage reduction so you know exactly how much space you saved.

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100% Private

All compression processing happens in your browser using PDF.js and PDF-lib. Your documents are never uploaded.

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Email-Friendly Output

Compress large PDFs to under email attachment limits (10–25 MB) without switching to a different file format.

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Always Free

No account, no watermarks, no size limits. Compress as many PDFs as you need for free.

Frequently Asked Questions

❓ Is the PDF Compressor free to use?
Yes, completely free with no limits, no watermarks, and no account required. Compress as many PDF documents as you need at no cost.
❓ Is my data secure? Does it upload my files?
Your PDF files are never uploaded to any server. All compression work happens locally in your browser using PDF.js and PDF-lib. Sensitive documents remain entirely private on your device.
❓ Why is the compressed PDF sometimes larger than the original?
Text-only PDFs with vector content, fonts, and no embedded images are already very compact. When this tool re-renders them as rasterized JPEG images and wraps them in a new PDF, the resulting file can actually be larger. This tool is most effective on image-heavy, scanned, or photo-based PDFs.
❓ Does compression affect text readability?
At medium compression (65% JPEG quality, 1.0× scale), text remains clearly readable. High compression (35% quality, 0.7× scale) may cause slight blurring of small text. If you need the text to remain sharp, use Low compression or the Custom mode with a quality setting above 70%.
❓ What file formats are supported?
Only PDF files (.pdf) are accepted as input. The compressed output is also a PDF file, named with a "-compressed" suffix for easy identification. All standard PDF viewers can open the resulting file.