PDF Compressor

Almost every free PDF compressor does the same thing without telling you: it takes a picture of each page and throws the original away. On a scanned document that is exactly right, and the file often shrinks by eighty per cent or more. On a document that contains real text it is destructive — every word stops being selectable, searchable and readable by a screen reader, and the file frequently ends up bigger than it started.

This tool checks which kind of document you have opened before offering anything. If it finds real text, it recommends the safe option and warns you plainly if you choose to flatten it anyway. If it looks like a scan, it recommends flattening, because that is where the large savings genuinely are.

The safe option rebuilds the file using cross-reference and object streams, which many older PDF producers do not use. Nothing is re-encoded, so text, fonts and images are untouched and the document is identical to read. Savings are typically a few per cent, occasionally much more on a file written by old software — modest, but never at a cost.

Flattening renders each page and stores it as a JPEG, at a resolution and quality you choose. Page sizes are preserved exactly, so a document meant for A4 still prints as A4 rather than quietly changing shape. Three levels are offered, and the middle one is a sensible balance for most scans.

If the result comes out larger than the original, the tool says so and tells you to keep what you had, instead of handing you a worse file with a success message. Everything runs on your device — the PDF is never uploaded, which matters because the documents people compress are usually contracts, statements and identity paperwork.