Quick answer: OCR is software that recognises the letters in a picture of text, such as a scan or a photo of a page, and turns them into real text you can search, select and copy.
OCR (Optical character recognition) explained
OCR, or optical character recognition, reads the letters in an image and turns them into text. A scanner or a phone camera only takes a picture of a page: to a computer, a scanned contract is the same as a photo of a cat. You can't search it with Ctrl+F, select a sentence or copy a figure. OCR fixes that.
The result comes in two common forms. A searchable PDF keeps the original page images and adds an invisible layer of text behind them, so the document looks the same but search and copy work. Plain text gives you only the words, ready to edit, translate or paste somewhere else.
Accuracy depends on the scan. Sharp, straight, well-lit pages in a common typeface come out nearly perfect; handwriting, faint photocopies, skewed photos and unusual fonts cause mistakes, so check names and numbers before relying on them.
How to get a good OCR result
- Scan at 300 dpi or take the photo square-on in good light. Blurry or very small text is the main cause of errors.
- Pick the right language. OCR uses a dictionary and alphabet for each language; the wrong one turns accents and letters into nonsense.
- Rotate pages upright first if they were scanned sideways.
- Keep the original. A searchable PDF still contains the page images, so nothing is lost if a word was misread.
OCR, PDF to text and PDF to Word
| You have | You want | Use |
|---|---|---|
| A scanned PDF or photo | Search and copy, same look | OCR to a searchable PDF |
| A scanned PDF or photo | Just the words | OCR to text (image to text) |
| A PDF made from a document (text already selectable) | The words | PDF to text, no OCR needed |
| A PDF with selectable text | An editable document | PDF to Word |
Quick test: if you can select a word in the PDF, it already has text and doesn't need OCR.
Frequently asked questions
What does OCR stand for?
Optical character recognition: software that recognises letters in an image and turns them into text.
Can I OCR a PDF for free without uploading it?
Yes. Our OCR PDF tool runs the open-source Tesseract engine in your browser, in 19 languages, so the PDF stays on your device.
Does OCR read handwriting?
Only poorly. OCR is built for printed text; neat block capitals sometimes work, joined-up handwriting usually does not.
Does OCR change how my PDF looks?
Not when you make a searchable PDF: the original page images stay and an invisible text layer is added behind them.
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