How to Compress a PDF and Reduce File Size

Why can a PDF file be so large?

A PDF can contain much more than text. High-resolution photos, scanned pages, embedded fonts and graphics can make the file many times larger than a simple text document.

Scanned PDFs are often especially large because every page may effectively be stored as an image.

Want to try the idea yourself? Use the PDF Compressor.

What does PDF compression do?

PDF compression tries to reduce the amount of data needed to store the document. This may include compressing or downsampling images and removing unnecessary data.

The aim is to make the file smaller while keeping it readable and useful.

If you want to explore this topic further, see Useful Free PDF Tools You Can Use in Your Browser.

File size vs quality

Stronger compression can produce a smaller PDF, but image-heavy pages may lose visible detail. A document containing mainly text can often tolerate more reduction than a photography portfolio or design proof.

The best setting therefore depends on what the PDF is for.

When should you compress a PDF?

Compression is useful when a PDF is too large to email, upload to a form, store efficiently or share on a website.

If a service has a strict upload limit, aim below that limit rather than exactly on it because file-size reporting can vary slightly.

Compress a PDF in your browser

The PDF Compressor lets you choose a PDF and reduce its size without manually rebuilding the document. Compare the compressed result with the original before discarding your source file.

If quality matters, open several pages after compression and check small text, diagrams and photographs at normal viewing size.