What OCR does for a scanned PDF
When you scan a paper document, the PDF contains only pictures of pages. You cannot search for a word, copy a paragraph, or have a screen reader read it aloud. Optical Character Recognition (OCR) reads those pictures, works out which words they contain, and adds that text back to the PDF as an invisible layer behind the original image. The page looks identical, but now it behaves like a real digital document.
How OCR PDF works here
You choose up to three languages that appear in your document, and PDF Studio runs the open-source Tesseract recognition engine over each page. The recognised words are placed at the same positions as the printed words, so selecting and searching text lines up with what you see on the page.
Unlike most tools on this site, OCR runs on our server rather than in your browser, because recognition is very demanding on processing power. Your file is sent to the server for processing; see our Privacy Policy for how data is handled.
Getting accurate results
Accuracy depends mostly on the scan. Clear, straight, well-lit scans of printed text at 200–300 DPI recognise very well. Blurry photos, skewed pages, faint ink, and unusual fonts reduce accuracy, and handwriting is generally not recognised reliably. Choosing the right language matters: selecting the wrong one produces gibberish, and adding a second language helps with documents that mix two, such as English text with Spanish names.
Limits and next steps
To keep processing fast for everyone, OCR accepts files up to 30 MB and 50 pages per run. For longer documents, split them with Split PDF and process the parts separately.
Once your document is searchable, you can copy text out of it, run Extract Text to save it as a plain text file, convert it with PDF to Word, or have the AI Summarizer condense it.