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.

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: 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. Runs entirely in your browser, free, no signup.

Last updated 2026-05-01

Good to know

OCR turns a picture of text back into real, selectable characters. A scanned PDF is just an image wrapped in a page, so Ctrl/Cmd+F finds nothing and screen readers see a blank page. This tool recognizes the words and writes them back as an invisible layer sitting exactly under the visible image, so the page looks untouched while search, copy and assistive technology all suddenly work.

Input quality is everything. The engine renders pages at 200 DPI, but recognition accuracy climbs sharply when the source scan itself is 300 DPI or higher. Clean, high-contrast printed text lands in the 95–99% range; faint photocopies, decorative fonts, tables and especially handwriting drag that down fast. Scanning in grayscale rather than color, and running a crooked scan through Rotate PDF first, both pay off.

Pick the correct language before you start — the model is trained per language, and choosing the wrong one will happily invent plausible-looking nonsense for accented characters. OCR is also genuinely CPU-heavy: budget a few seconds per page, so a long document can take several minutes. If you only need the raw words rather than a searchable copy, the lighter PDF to Text is quicker for PDFs that already contain a text layer.

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.