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Compress PDF Online Free

Reduce your PDF file size for easy sharing via email. Fast, free and completely private.

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Drop your PDF here
or click to browse — files stay on your device

How to Compress a PDF

1

Upload PDF

Select the PDF file you want to reduce in size.

2

Choose Level

Select your compression level — from light to maximum compression.

3

Download

See exactly how much space was saved and download the optimised file.

Compression Levels Explained

🟢 Low

10-20% reduction. Best for documents where visual quality is critical, such as photographs or design files.

🟡 Medium

30-50% reduction. Ideal for business documents, reports and presentations with a good balance of quality and size.

🟠 High

50-65% reduction. Suitable for documents that will be viewed on screen where some quality trade-off is acceptable.

🔴 Maximum

65-80% reduction. Best when file size is the priority. Quality is visibly reduced but files are very small for email.

PDF Compression — Complete Guide

PDF compression reduces file size by optimising the content stored within the document. Modern PDFs often contain high-resolution images, embedded fonts, and metadata that can be significantly reduced without visible quality loss for everyday use.

How Our Compression Works

Our PDF compressor uses pdf-lib to re-process your document. It optimises the internal object structure, applies image downsampling at the quality level you select, and removes redundant data that accumulates from repeated editing and saving. All processing happens in your browser — your document is never sent to any server.

When to Use PDF Compression

Compress PDFs when you need to email large documents (most email providers limit attachments to 10-25MB), upload files to web forms with size limits, reduce storage space for archived documents, or improve loading times for PDFs shared on websites. Scanned documents and photo-heavy PDFs typically benefit the most from compression.

Frequently Asked Questions

How much can I reduce my PDF size?

Results vary by document type. Image-heavy or scanned PDFs typically compress 40-80%. Text-only PDFs may only reduce 5-20% as text is already efficiently stored.

Will compression affect text readability?

No. Text in PDFs is stored as vector data which is not affected by compression. Only embedded images may show quality changes at higher compression levels.

Can I compress a PDF multiple times?

Yes, but with diminishing returns. After the first compression, further compression provides little additional reduction as the data is already optimised.

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