What is OCR and When Should You Use it on a PDF?
Updated · FlowToPDF Team
OCR (Optical Character Recognition) transforms scanned images into searchable text. Here is when and why you need it.
What is OCR?
Optical Character Recognition (OCR) is technology that reads text from images and scanned documents and converts it into machine-readable text.
Without OCR, a scanned PDF is just an image — you cannot select text, search for keywords, or copy content.
When to Use OCR
- You scanned a physical document (receipt, contract, book page)
- You received a PDF that was saved from a scanner
- You cannot select or copy text in a PDF viewer
OCR Language Support
FlowToPDF's OCR tool supports: English, Spanish, French, German, Portuguese, and Italian. Selecting the correct language for your document improves accuracy significantly.
Accuracy Expectations
OCR accuracy depends on:
- Scan quality — Higher resolution scans produce better text recognition
- Font clarity — Standard fonts are recognized more accurately than handwriting
- Layout complexity — Simple single-column text converts best
For handwritten documents, OCR accuracy is generally low. Best results come from cleanly printed, high-contrast text.
After OCR
Once OCR is applied, the PDF becomes searchable. You can open it in any PDF viewer and use Ctrl+F (or Cmd+F on Mac) to search for specific words.