Extract Text from Scanned PDFs — Free OCR Guide

OCR (Optical Character Recognition) converts images of text into machine-readable, searchable, and copyable text. It's essential for scanned documents, photos of documents, and image-based PDFs — the kind you get from a scanner or a phone camera.

How OCR Works

OCR engines analyze the shapes in an image, identify patterns that match known characters, and output the recognized text. Modern OCR engines like Tesseract (which we use) combine pattern matching with language models to achieve high accuracy — often 98%+ on clean, well-scanned documents.

Getting the Best OCR Results

1. Scan at the Right Resolution

300 DPI is the sweet spot for OCR. Below 200 DPI, character shapes become ambiguous and accuracy drops significantly. Above 400 DPI, file size increases with minimal accuracy improvement. If you're scanning documents specifically for OCR, set your scanner to 300 DPI in grayscale or color.

2. Ensure Good Lighting and Contrast

For phone photos of documents, even lighting without shadows is critical. High contrast between text (dark) and background (light) helps the OCR engine distinguish characters. Avoid flash photography — it creates hotspots that confuse the engine.

3. Keep the Document Flat and Straight

Skewed or warped text reduces OCR accuracy dramatically. If photographing a document, place it on a flat surface and shoot from directly above. For curved pages (book spines), press the page flat or use a scanner.

4. Choose the Right Language

OCR engines use language-specific character sets and dictionaries. Running OCR with the wrong language setting (e.g., English OCR on a French document) produces garbled output. Our OCR tool supports multiple languages — select the correct one before processing.

What OCR Can and Cannot Do

✅ Clear, printed text at 300 DPI: 98%+ accuracy
✅ Typewriter text: 95%+ accuracy
⚠️ Handwriting: 60-80% accuracy (highly variable — neat handwriting fairs better)
⚠️ Low-contrast text (e.g., light gray on white): 70-85% accuracy
❌ Stylized or decorative fonts: Often fails completely
❌ Text in complex backgrounds (e.g., text over a photo): Poor results
❌ Vertical or rotated text: May be missed entirely

What to Do with Extracted Text

Once you've extracted text via OCR, you can:

Save as a searchable PDF: Our OCR PDF tool creates a PDF layer with the recognized text, making it searchable and copyable
Export to Word: Use our PDF to Word converter to create an editable DOCX
Extract plain text: Use PDF to Text for raw text extraction
Convert to Markdown: Try PDF to Markdown for clean, structured markdown output

Privacy Note

OCR processing requires server-side computation (Tesseract runs on our servers). Your files are transferred over 256-bit TLS encryption and automatically deleted within 24 hours. No human ever views your documents. For sensitive documents, consider using offline OCR software like Tesseract Desktop.

Try it now: Free OCR for Scanned PDFs — extract text from your scanned documents.