What Is OCR? How Computers Read Scanned Text
OCR stands for optical character recognition, and it's the technology that lets software "read" text that only exists as an image — a scanned page, a photographed document, a screenshot — and turn it into real, usable text data.
The core problem OCR solves
A scanned document, however sharp and legible it looks to a human, is really just a grid of colored pixels as far as a computer is concerned — no different in kind from a photo of a mountain. There's no actual text data in the file, which means it can't be searched, selected, or copied. OCR bridges that gap by analyzing the visual patterns on the page and identifying which patterns correspond to which letters and words.
How it works, at a high level
Modern OCR uses models trained on enormous numbers of examples of text in various fonts, sizes, and conditions to recognize character shapes reliably, even accounting for some noise, skew, or imperfect scan quality. The result is a layer of actual, recognized text that can be matched precisely to its position on the original image — which is why OCR'd documents typically keep looking exactly like the original scan, with the recognized text sitting invisibly underneath.
What affects accuracy
Clean, high-resolution scans of standard printed fonts get the most accurate results. Accuracy drops with low resolution, skewed or rotated pages, poor lighting or contrast, unusual fonts, and handwriting — cursive handwriting especially remains genuinely difficult, since it lacks the consistent, separated letterforms that OCR relies on.
What OCR unlocks once it's done
Once a document has been through OCR, you can search it for specific words, select and copy text out of it, and convert it into a genuinely editable format far more reliably than trying to work from the raw scan. It's the difference between a document you can only look at and one you can actually use.
OCR PDF adds this recognized text layer directly in your browser, without changing how the scanned pages look. Once OCR'd, PDF to Word can turn the result into a fully editable document.