Optimize PDF
What does OCR PDF do?
OCR PDF adds a searchable, selectable text layer to scanned PDF pages in the browser. The original page image and page order are kept. It does not rebuild the layout as an editable Word file. You can let it detect a language or choose one. Accuracy varies with scan quality, so review names, numbers, handwriting and uncommon characters.
How to use OCR PDF
- 1Choose one PDF
Open OCR PDF and select a single scanned or image-based PDF. Unlock protected files first. One PDF is accepted per task.
- 2Choose the OCR language
Use automatic detection or pick the language that matches the page. Automatic mode downloads script data as needed. Choosing the wrong language lowers accuracy.
- 3Keep a searchable layer
Leave the searchable text option on unless you only need recognized text in memory. The usual result is a PDF that still shows the original page image with hidden searchable text.
- 4Run OCR locally
Each page is rendered and recognized with Tesseract in the browser. Language models load from this site’s tessdata files; the document itself is not uploaded to an application server.
- 5Review the result
Search for names, amounts and rare characters. OCR does not reconstruct source layout for editing. Convert to Word or Excel only after you accept the recognized text.
Supported files and limits
- Output format: PDF
- Input: PDF
- Output options: automatic or chosen OCR language; searchable text layer
- one PDF per task; recognition depends on scan quality and language data
- Files stay on this device and are removed when you close the page.
Recognition depends on scan quality and language data. Names, numbers, handwriting and uncommon characters can be wrong. OCR adds a text layer; it does not rebuild an editable layout.
What the output keeps
- original page image
- page order
The original page image remains visible, and page order is unchanged. When the searchable option is on, recognized characters are stored as a text layer you can search and select.
What may change or be lost
- recognition accuracy for names, numbers, handwriting and uncommon characters
OCR can misread similar glyphs, faded scans, stamps and handwriting. It does not restore fonts, columns or vector drawings. Automatic language detection can pick the wrong script on mixed pages.
When not to use this tool
Do not use OCR PDF as a substitute for proofreading, as a layout-preserving Word conversion, or as a way to recover text from an encrypted file you are not authorized to open. Born-digital PDFs that already have a correct text layer usually do not benefit.
If processing fails
If recognition is empty, the page may be too dark, too small or in an unsupported script — raise scan quality or pick the correct language. If the language pack fails to load, check the network for tessdata and retry. Encrypted files must be unlocked first. Large page counts can run for a long time and may exhaust memory.
Privacy boundary
Page images are recognized in this browser. The PDF contents are not sent to a PDF Smart Kit application server. OCR language models are static site assets. Close the page to clear the active task from memory.
Testing evidence
Last tested: · Test browser: Desktop Chrome via Playwright Chromium · Product version: 1.0.0
Sample: Image-based PDF page with printed Latin text · 1 pages
What was checked
- The download is a valid PDF.
- A searchable text layer is present after OCR on a printed sample.
- The selected language pack is the one used for recognition.
Known failures and limits
- Handwriting, low-contrast scans and uncommon fonts still need manual review.
- OCR does not restore original document structure or fonts.