OCR PDF
Extract text from scanned PDFs using Tesseract.js running entirely in your browser. Supports 100+ languages with adjustable render quality. No uploads, no servers.
Private Browser-Based 100+ Languages
Drop a scanned PDF here or click to browse
Accepted: PDF files only. Maximum size: 50 MB
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How It Works
- Upload a scanned PDF (drag or click)
- Select language and render scale (higher = better accuracy)
- Click Start OCR to begin extraction
- Each page is rendered to canvas at high resolution
- Tesseract.js LSTM neural network recognizes characters
- Review, edit filename, then download or copy
Features
- Tesseract.js v5 LSTM engine (near-human accuracy)
- 100+ languages including CJK, Arabic, Cyrillic
- Adjustable render scale (1.5x, 2x, 3x) for quality control
- Per-page confidence scoring and processing stats
- Keyboard shortcut: Ctrl+D to download
- Complete privacy: all processing in your browser via WASM
- No file size upload limits (50 MB client-side cap)
Frequently Asked Questions
What is OCR and how does it work on PDF files?
OCR (Optical Character Recognition) is a technology that converts images of text into machine-readable characters. When applied to scanned PDFs, the tool renders each page as a high-resolution image, then uses the Tesseract.js LSTM neural network to detect and recognize text patterns. The recognized characters are assembled into words and paragraphs, producing editable and searchable plain text output.
Which languages does this OCR tool support?
This tool supports over 100 languages through the Tesseract.js engine, including English, Spanish, French, German, Italian, Portuguese, Dutch, Polish, Russian, Japanese, Korean, Chinese (Simplified and Traditional), Arabic, Hindi, Thai, Vietnamese, and Turkish. The LSTM-based recognition model provides high accuracy across Latin, Cyrillic, CJK, and RTL scripts.
Is my PDF data secure when using this OCR tool?
Yes. This tool processes your PDF entirely within your browser using WebAssembly (WASM). Your files are never uploaded to any server. All rendering and text recognition happen locally on your device, ensuring complete privacy. Once you close or refresh the page, no trace of your document remains.
How can I improve OCR accuracy on low-quality scans?
To improve accuracy on low-quality scans, increase the render scale to 3x before starting the OCR process. Higher render scales produce larger canvas images that give the neural network more detail to work with. Additionally, ensure the source PDF has adequate contrast between text and background. Documents with very small fonts, heavy noise, or skewed pages may yield lower confidence scores.
What file size and page limits apply to this OCR tool?
The tool accepts PDF files up to 50 MB in size. There is no hard limit on page count, but processing time increases with each page since every page must be rendered and analyzed individually. For large documents, the progress bar and per-page status updates keep you informed. Processing speed depends on your device hardware and the selected render scale.