A scanned PDF looks like text, but to a computer it's just a picture. You can't search it, select it, or copy from it. OCR (Optical Character Recognition) reads the words in the image and adds a real text layer — turning a flat scan into a searchable document. And it can run entirely in your browser.
What OCR does here
The OCR PDF tool recognizes the text on each page and places it as an invisible layer on top of the page image. The pages look exactly the same, but now you can:
- Search the document with Ctrl/Cmd+F
- Select and copy text
- Have screen readers read it aloud
How it works
Each page is rendered with pdf.js and passed to Tesseract — a WebAssembly OCR engine — running in your browser. The recognized words are positioned over the page image with pdf-lib at zero opacity, so they're selectable and searchable but don't alter the look. Your document never leaves your device.
Step-by-step
- Open the OCR PDF tool
- Drag and drop your scanned PDF
- Choose the document's language (English, Vietnamese, French, German, Spanish, or Portuguese)
- Click OCR & download searchable PDF
The first run downloads the OCR engine and language model (a few MB); after that it's cached.
Tips for accurate OCR
- Higher-resolution scans recognize far better than blurry ones — 300 DPI is ideal
- Pick the right language so the correct model loads
- Straighten pages before OCR; skewed text lowers accuracy
- Clean scans (good contrast, no shadows) give the best results
When to use OCR
| Your PDF… | Do this |
|---|---|
| Is a scan / photo with no selectable text | Run OCR PDF |
| Already has selectable text | You don't need OCR — use PDF to Word to extract it |
| Is a single image | Use Image to Text |
Frequently asked questions
Is my PDF uploaded? No. OCR runs entirely in your browser with WebAssembly Tesseract.
Why does the first run take a while? The engine and language model download once, then are cached. Processing time then depends on page count and your device.
Will the pages look different? No — the text layer is invisible. The pages look identical; only searchability changes.
Is it free? Yes — no account, no watermark, no limits.
Related tools
- PDF to Word — extract recognized text into an editable document
- Scan to PDF — create the scan in the first place
- Image to Text — OCR a single image