OCR a scanned PDF privately in your browser

A flat scan is just pictures of pages. You cannot search, copy a quote, or highlight a clause until optical character recognition (OCR) rebuilds a text layer. Cloud OCR is accurate and convenient — and it receives every pixel of the scan. Private OCR runs the engine in your browser instead.

When OCR is worth it

• Phone photos of contracts or whiteboard notes
• Scanner PDFs with no text layer
• Archived faxes and stamped forms you need to search later
• Language-specific docs where you can pick the right OCR language pack

How StackPDF keeps OCR local

OCR uses Tesseract compiled for the web, with language data loaded as needed. Recognition happens on your device; StackPDF is not an intermediary that stores the scan for “processing.” First use of a language may download a pack; after that, repeat jobs stay snappier and can work offline depending on cache.

Tips for better recognition

1. Prefer straight, well-lit scans; rotate skewed pages first.
2. Crop dark scanner borders that confuse layout.
3. Match OCR language(s) to the page — English on a Spanish form will misread accents.
4. Expect imperfect tables and handwriting; OCR is assistive, not a notary.
5. Compress huge image-only PDFs only after you are happy with the text layer, or keep two versions.

Related steps

Scan to PDF if you are capturing from a camera, then OCR. Use Privacy Scanner or Redact before sharing if the newly searchable text surfaces secrets you meant to hide.