PDF Tool
Compress PDF
Reduce PDF size with clear quality presets designed for email, uploads, and fast sharing.
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How Compress PDF works
How this tool works
Compress PDF rebuilds the pages of your document in the browser at a quality level you choose, aiming for a smaller file. Low keeps the most detail, medium balances size and readability, high reduces the most while staying readable.
When to use it
Use it when a scan or a photo-heavy PDF is too large for an email attachment, an upload form, or a messaging app. For pure text PDFs the benefit is usually small.
What to expect
Results depend entirely on the document: scanned and image-heavy PDFs usually shrink clearly, while already efficient text PDFs may barely change. If the compressed result would be larger than your original, PDFCustom keeps your original file instead.
Limits and important notes
Compression re-encodes pages as images, so it is not lossless and small quality differences can appear. No fixed percentage can be promised, because the outcome depends on how the PDF was created, and text in the rebuilt pages is no longer selectable.
A practical example
A 12 MB scanned contract shrinks clearly with the medium preset, while a 300 KB text-only invoice stays roughly the same size — in that case you simply keep the original.
Related tools
FAQ
Why didn't my PDF get smaller?
Which compression level should I choose?
Is compression lossless?
About this tool
Compress PDF rebuilds pages in the browser into a lighter PDF when practical, while being honest when a file cannot be reduced much without a stronger server-side engine. It is best suited for scanned and image-heavy PDFs.