Scanned Korean documents — contracts, certificates, reports — contain image-based text that cannot be searched or copied. Free OCR technology can recognize Hangul characters and convert them into selectable, editable text. Here is how.
Go to pdfeditor.onl/ocr-pdf. No account or installation required. The OCR engine runs directly in your browser using Tesseract.js, which supports Korean (Hangul) text recognition.
Click to upload or drag your PDF into the tool. The tool renders each page as a high-resolution image for OCR processing.
Tip: For best Korean OCR accuracy, use scans at 300 DPI or higher. Blurry or low-resolution scans significantly reduce recognition accuracy for Hangul characters.
In the language settings, choose Korean (한국어). The OCR engine will use the Korean character model to recognize Hangul, Hanja, and mixed Korean-English text.
After scanning, text blocks appear overlaid on the page. Review each block and correct any recognition errors — especially for similar-looking Hangul characters or small font sizes.
Click Download PDF. The result is a PDF with an invisible text layer over the original image — the document looks the same but the Korean text is now searchable and copyable.
Yes. Tesseract can handle mixed-language documents. For best results with Korean-English mixed text, select Korean as the primary language — the engine will recognize Latin characters as well.
Horizontal text recognition works well. Vertical Korean text (sometimes used in traditional documents) may have lower accuracy — try rotating the page to horizontal if possible.
Yes — completely free, no account, no watermarks on the output PDF.