PDF OCR (Searchable PDF)
Run OCR on a scanned PDF to make it searchable and copy-able, with an invisible text layer behind every page.
Quick answer: Run OCR on a scanned PDF to make it searchable and copy-able, with an invisible text layer behind every page.
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Frequently asked questions
- What is OCR for PDFs?
- OCR (optical character recognition) reads the pixels of scanned pages and recognises the words. We then write those words back into the PDF as an invisible text layer, so search, copy and screen readers all work.
- Can OCR make a scanned PDF searchable?
- Yes — that's exactly what it does. After OCR, Ctrl/Cmd+F in any PDF reader will find words inside the scan.
- How accurate is PDF OCR?
- Tesseract is typically 95-99% accurate on clean printed text at 300 DPI. Accuracy drops on low-quality scans, handwriting, and unusual fonts. Higher-resolution source scans give the best results.
- Does OCR support multiple languages?
- Yes. Pick from English, Dutch, German, French, Spanish or Italian. Each language model downloads on first use (about 10 MB) and is cached.
- Can OCR handle rotated pages?
- It handles small skew well. For pages rotated 90° or 180°, run them through Rotate PDF first, then OCR.
- Is there a page limit?
- No fixed limit. OCR is CPU-heavy though, so each page takes a few seconds — a 100-page PDF can take several minutes on a typical laptop. The progress bar shows live status.
- Will OCR change the look of my PDF?
- No. The page image is preserved exactly; the OCR text is added as an invisible layer behind it. The visible page looks identical to the original.
- Is OCR safe for sensitive documents?
- Yes. The whole process runs in your browser — the PDF and the OCR results never leave your device.
- Can I copy text after OCR?
- Yes. Open the resulting PDF in any reader (Acrobat, Preview, browser PDF viewer), select text, and paste — the OCR'd words are what gets copied.
- Why does OCR miss some characters?
- Common causes: low-resolution scans, unusual fonts, very small text, or text on a textured background. Re-scan at 300 DPI in greyscale (or use our PDF to Grayscale tool first) for the best results.