How much can I compress a PDF file?

The compression ratio depends on the original file. PDFs with high-resolution images can often be reduced by 50-90%. Text-heavy documents with few images may see smaller reductions.

Does compressing a PDF reduce its quality?

Our tool offers multiple compression levels. The "High quality" preset preserves maximum visual fidelity, while "Low quality" achieves the smallest file size with some image quality reduction.

What is the difference between Resize PDF and Compress PDF?

Compress PDF (this tool) strips metadata and optimizes internal structure. Resize PDF changes the actual image resolution inside the document. For maximum reduction, use both tools together.

Online PDF optimizer

Online PDF optimizer/compressor

Reduce the file size of your PDF documents using our free online PDF optimizer. This tool compresses PDF files using three different quality levels, making them smaller and easier to share by email, upload to websites, or store on your device.

How PDF Compression Works

Upload your PDF file by dragging it to the upload area or clicking to browse.
Choose a compression level: Low, Medium, or High quality.
Click "Optimize!" to compress the file.
Download your optimized PDF and check the file size reduction shown on screen.

Compression Levels

High quality (prepress): Minimal compression, best for professional printing. Images are kept at 300 dpi.
Medium quality (ebook): Good balance between file size and visual quality. Images are downsampled to 150 dpi — ideal for on-screen viewing and email.
Low quality (screen): Maximum compression for the smallest file size. Images are reduced to 72 dpi. Best for quick previews and web uploads.

When to Use This Tool

Your PDF is too large to send via email (many email providers limit attachments to 10-25MB).
You need to upload documents to a website with file size restrictions.
You want to save storage space on your device or cloud storage.
Large scanned documents need to be made more manageable.

This tool processes your files entirely on our server — no software installation required. It works on any device with a web browser.

All uploaded files are automatically deleted from our servers within 1 hour of upload.

Need more control over file size? Try our PDF resize tool to change the page resolution directly, or our grayscale converter for additional size reduction.

Frequently Asked Questions

How much can I compress a PDF file?: The compression ratio depends on the original file. PDFs with high-resolution images can often be reduced by 50-90%. Text-heavy documents with few images may see smaller reductions.
Does compressing a PDF reduce its quality?: Our tool offers multiple compression levels. The "High quality" preset preserves maximum visual fidelity, while "Low quality" achieves the smallest file size with some image quality reduction.
What is the difference between Resize PDF and Compress PDF?: Compress PDF (this tool) strips metadata and optimizes internal structure. Resize PDF changes the actual image resolution inside the document. For maximum reduction, use both tools together.