PDF Basics · Updated September 25, 2026
How do I make a scanned PDF searchable (OCR)?
Short answer
Run OCR (optical character recognition) on the scanned PDF; it recognizes the characters in the page images and adds an invisible text layer so the document becomes searchable, selectable, and usable by AI tools.
How to tell if a PDF is scanned
Try selecting text — if nothing highlights, the page is an image. Our free PDF Inspector reports "no text layer" for scanned files outright, so you do not have to guess.
What OCR actually does
OCR analyzes the page image, recognizes character shapes, and writes an invisible text layer aligned with the picture underneath. The page looks identical, but now Ctrl-F finds words, text can be copied, and every tool that reads text — chat, takeoff, address scanning — starts working.
Quality factors
- Resolution — 300 dpi or better scans recognize more accurately.
- Skew and noise — straight, clean pages beat crooked fax-quality ones.
- Handwriting — print recognizes well; handwriting is unreliable.
- Mixed pages — only the scanned pages need OCR; run it on the whole file anyway.
Doing it in PDFDepth
OCR is available per document or across a folder. The Auto-Name Sheets folder operation even uses OCR to read title blocks and rename sheets automatically — one of the fastest wins on a scanned plan set.
Key takeaways
- A scanned PDF is images until OCR adds a text layer.
- Check with text selection or the free PDF Inspector.
- Clean, high-resolution scans produce the best OCR.
- OCR unlocks search, copy, chat, takeoff, and scanning tools.
Related questions
No — it adds an invisible text layer behind the page image; appearance is unchanged.
Do it in PDFDepth
In the app: Command line → CLOUD:OCR, then use Chat with PDF or AI Takeoff on the result
Try it free — no signup, no upload
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Put it into practice
Everything above runs inside the PDFDepth workspace — free for 14 days, no credit card.
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