OCR PDF: make a scanned PDF searchable

What OCR does to a PDF

A scanned PDF is a stack of pictures of pages. You can read it, but you can't search it, select a sentence or copy a figure. OCR, optical character recognition, reads the letters in those pictures. This tool places the recognized words as an invisible text layer in the same position as the printed words, so the PDF looks exactly as before but now behaves like a text document.

How to OCR a PDF

Drop the scanned PDF above and pick the language of the text. Press the start button. Each page is rendered at twice its size, read by Tesseract and then the words are written into a copy of your original PDF. A progress bar shows which page is being read. When it finishes, download the file ending in -searchable.pdf and press Ctrl+F or Cmd+F in your PDF reader to check it.

Languages and accuracy

The OCR models cover English, Spanish, French, German, Italian, Portuguese and Dutch. Clean, straight scans at 300 DPI give the best results. Skewed pages, handwriting, low contrast and decorative fonts lower accuracy, and words the engine misreads will also be found under the wrong spelling. The hidden text uses a standard Latin font, so characters outside Western European alphabets are skipped.

Speed and first run

OCR is heavy work. Expect a few seconds per page on a laptop and longer on a phone. The first run downloads the Tesseract engine and the language model, which your browser then caches. Your PDF itself is never uploaded, only the engine files come from the network.

Your file stays on this device

Convertur reads the file in this browser tab and builds the result there. The file is never sent to a server. Larger browser engines load only when this tool needs them.

Before you start

Input: PDF. Output: searchable PDF. The settings appear before anything runs, so you can check them first. Your original file is never changed.

If layout, notes, forms, signatures or fonts matter, check the new PDF page by page. A file that opens is not the same as a file that looks right.

Keep the original until you have opened and checked the result. The work happens in this browser tab, so the size you can handle depends on your device's memory, your browser and the file itself.

How to make a scanned PDF searchable

1. Drop a scanned PDF into the box above.
2. Choose the language of the document.
3. Start OCR and wait while each page is read.
4. Download the searchable PDF and test it with your reader's search.