Why scanned PDFs are so large — and how this fixes it
When you scan a document, each page becomes a high-resolution image embedded in the PDF. A 300 DPI colour scan of one A4 page can be over 1MB on its own. The compressor lowers the resolution and image quality to the point where the document is still clearly legible but the file is a fraction of the size — the same trade-off a photocopier makes between quality and speed. For a 100KB target, aim to scan in grayscale rather than colour where the document allows it; colour scans carry roughly three times the data.
Frequently asked questions
Does this work on any PDF?
It works best on scanned or image-based PDFs — the kind most 100KB upload limits are meant for. Text-heavy PDFs with selectable text compress less and their text may become part of a page image.
Is my document uploaded anywhere?
No. The PDF is processed in your browser using its own rendering engine. The file never leaves your device — you can disconnect from the internet after the page loads and it still works.
The result is above 100KB — why?
Some documents can't reach a target without becoming unreadable — many pages, or dense colour scans. The tool returns the smallest legible version and tells you. Try scanning in grayscale, or use a slightly higher target.