Pro · local browser tool
Make scanned PDFs searchable—on your device.
Add a transparent text layer to scanned PDFs with browser-based OCR. The original page image stays visible while recognized text becomes searchable and copyable.
This is a Pro feature. A verified account and active Founding Beta access are required to test it free during beta. Places, end time and daily allowance are subject to the current rules. Paid checkout is not available. Beta rules · Plans and limits
How to use OCR PDF
- 01Open a scanned PDF
- 02Choose English, Simplified Chinese, or both
- 03Run OCR and download the searchable PDF
Why PDFbuff
A direct path from file to result.
Local Tesseract OCR
English and Simplified Chinese
Original page image retained
300–600 DPI processing options
Know the boundary
What this tool does—and what it does not.
OCR accuracy depends on scan quality, orientation, typeface, and language. Handwriting and complex layouts may produce errors and should be reviewed.
OCR PDF FAQ
Before you start.
Does OCR send my scan to a server?
No. Recognition runs locally in the browser using WebAssembly.
Which languages are supported?
The current workspace supports English, Simplified Chinese, and a combined Chinese-plus-English mode.
Why does PDFbuff start at 300 DPI?
Higher-resolution input materially improves recognition for Chinese text. Lower settings can produce a convincing-looking PDF with an unusable text layer.
Is OCR always accurate?
No. Review important names, numbers, and legal text before relying on the result.
Ready when you are