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OCR PDF

PDF OCR – Extract Text from Scanned PDF Free Online

Scan to searchable PDF. Turn image-only PDFs into documents with selectable, searchable text.

  • Runs in your browser
  • Nothing uploaded
  • No sign-up
  • Free, no daily limits
  1. 1Add your file
  2. 2Choose settings
  3. 3Download
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It is processed inside this browser tab and never uploaded, and it is gone when you close the page.

Good to know

  • Pick the content type that matches your scan: it is the biggest lever for accuracy.
  • 52 languages; each language model downloads the first time you use it.
  • The searchable PDF keeps the scan and adds an invisible text layer you can search.

Last updated

PDF OCR transforms scanned paper documents and image-only PDFs into fully searchable, selectable digital files directly in your web browser. Running Tesseract.js compiled to WebAssembly on your local device, the engine recognizes text glyphs across 52 languages, synthesizes an invisible text layer matching exact word bounding boxes, and injects it over the original page images using pdf-lib.

The client handles files up to 20 MB and processes up to 50 pages per batch. The original scanned artwork, stamps, and layout remain visually untouched, while characters become searchable via Ctrl+F, selectable with a cursor, and ready to copy into text editors. Once OCR adds selectable text to your scan, see how to edit PDF text to change wording or fix errors.

How it works

  1. 1. Select a scanned PDF

    Drag and drop your file into the upload zone or click to browse. The tool accepts files up to 20 MB and renders previews for up to 50 pages.

  2. 2. Choose language models and options

    Pick your document language from 52 supported models (English is default). Choose Performance mode (Auto, Lite, or Full) and configure the Content Type segmentation.

  3. 3. Click Make PDF Searchable

    The browser initializes WebAssembly workers. Language data is fetched once and cached in IndexedDB for subsequent offline runs, with live page-by-page progress.

  4. 4. Review and download

    Review the result in the Searchable PDF preview tab, copy text via the Extracted Text panel, or download the searchable PDF and plain-text .txt file.

When you'd use it

  • Indexing paper marks cards and educational certificates

    Physical diplomas, transcripts, and exam scorecards are routinely distributed as flat scans. Applying OCR makes candidate names, registration numbers, and grades searchable across document archives.

  • Digitising paper invoices, receipts, and tax records

    Smartphone photos of expense receipts lack computer-readable text. OCR extracts totals, vendor tax numbers, and dates into copyable text strings for accounting spreadsheets.

  • Searching long legal contracts and historical archives

    Physical contracts scanned decades ago require laborious manual reading. Adding a searchable text layer enables keyword searches across multi-page agreements instantly.

  • Processing multilingual governmental records

    TryDocsy supports dual-language recognition for documents that mix English with Indian regional scripts, including Hindi, Tamil, Telugu, Bengali, Gujarati, Kannada, Malayalam, and Marathi.

How the searchable PDF text layer works

A common misconception is that OCR converts a picture into typed paragraphs and rebuilds the page. In TryDocsy's pipeline (lib/pdf-ocr.ts and OcrClient.tsx), the original high-resolution page image is preserved as the visual backdrop.

Tesseract detects words, baseline positions, and bounding coordinates across the canvas. TryDocsy then draws invisible vector text glyphs directly on top of the corresponding image coordinates. When you select a sentence in Adobe Reader, Chrome, or Preview, your cursor highlights the invisible text layer while your eyes view the original scan underneath.

This dual-layer structure guarantees zero visual distortion: handwritten margin notes, official ink stamps, and graphical logos stay intact while the text becomes completely searchable.

System limits, performance modes, and device scaling

In OcrClient.tsx, the application enforces a 20 MB file size upload cap and loads up to 50 pages (Math.min(pdf.numPages, 50)) to maintain stable memory usage in browser tabs.

Rendering scale adapts dynamically via Math.min(profile.pdfMaxScale, Math.max(1.2, cap)) against a pixel budget of 4,000,000 pixels per page. On resource-constrained mobile devices, Lite mode processes pages sequentially to avoid out-of-memory crashes.

On multi-core laptops and workstations, Full mode allocates multiple Web Workers to process pages in parallel, drastically reducing recognition time on 30-page to 50-page documents.

Maximising OCR accuracy on difficult scans

Page Segmentation Mode (Content Type) is the primary lever for recognition fidelity. Use 'Dense paragraph / book' for book pages, 'Sparse / scattered' for tabular invoices and government identity cards, and 'Single line' for isolated license plates or headings.

The Enhance Image toggle applies automatic grayscale normalization, contrast stretching, and interpolation prior to OCR recognition. This significantly improves recognition rates on faint photocopies and carbon-copy forms.

Frequently asked questions

How do I make a scanned PDF searchable without Adobe Acrobat?

Upload your scanned PDF to TryDocsy PDF OCR, select the languages present in the document, and click Make PDF Searchable. The in-browser OCR engine processes the file locally using Tesseract.js and generates a searchable PDF with an invisible text layer, without requiring an Adobe Acrobat Pro subscription.

Why does my OCR PDF have selectable text but looks like an image?

TryDocsy creates a hybrid searchable PDF: the original scanned page image remains in full resolution, while an invisible text layer is layered directly over the words. This preserves the original visual layout, stamps, and signatures while allowing you to highlight, search, and copy text.

What is the file size and page limit for PDF OCR?

TryDocsy PDF OCR accepts documents up to 20 MB and processes up to 50 pages per document. This cap ensures smooth client-side execution within browser memory constraints.

Are my scanned documents uploaded to a cloud server?

No. The entire OCR pipeline, including page rendering, character recognition, and PDF re-assembly, runs inside your web browser. Only the one-time language dictionary models (1 to 2 MB) are downloaded, which are cached in your browser for offline use.

Can this OCR tool recognize handwritten cursive notes?

Tesseract.js is trained specifically on printed typography and fonts. It performs poorly on cursive or freehand handwriting. For best results, use clean, upright, printed documents.

What languages are supported?

The tool supports 52 languages, including English, Hindi, Bengali, Gujarati, Kannada, Malayalam, Marathi, Punjabi, Tamil, Telugu, and Urdu. You can select multiple languages simultaneously for bilingual documents.

Step-by-step guides using this tool

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