Make a scanned PDF searchable
For the PDF where Ctrl+F finds nothing: add the missing text layer without changing how a single page looks.
- Nothing is uploaded
- Works offline after first use
- Open source
- No watermark · limit is your device’s memory; phones hold less
Ctrl+F finds nothing in your scanned PDF? Add a hidden text layer on your device so search, select and copy work, with the pages looking exactly the same. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The first run downloads the text reader (about 6 MB) and the WebAssembly engine that runs it to your browser, and after that the tool works offline.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
If Ctrl+F in a PDF says no results for a word you can plainly see, the page is a picture: it came from a scanner, a phone scanning app or a fax, and the file holds a photograph of the paper rather than letters. This page reads that picture and lays the words invisibly over it, so search, highlighting and copy work like in any other PDF.
A worked example: a 40-page lease scanned at the letting agent and emailed to you as lease.pdf, and you want to find the clause about the deposit. Drop it here and press Make searchable. Every page is rendered and read in turn; the note under the download reports how many words were found and Tesseract’s average confidence. Open lease-searchable.pdf, press Ctrl+F, type deposit, and each mention is highlighted where it sits on the scan.
Mixed files are handled page by page. A report where most pages were typed but the signed last page was scanned only has that last page read; the typed pages keep their own, exact text. If a page came out badly, rescan it straighter or at a higher resolution, then run it again.
How it works
- Drop the PDF that will not search.
- Press Make searchable; pages with text already are skipped.
- Open the new copy and search it with Ctrl+F or Cmd+F.
In your browser, not on a server
pdf.js (Apache-2.0) renders each page in your tab at 300 dpi (large pages a little less). Tesseract (Apache-2.0), compiled to WebAssembly by tesseract.js with its English LSTM model, finds every word and its box; the engine and model, about 6 MB, are downloaded from this site on first use and cached. pdf-lib (MIT) then writes each word into the page as invisible text (render mode 3) in Helvetica, placed on the word’s baseline and stretched to the word’s width, so a search highlights the right spot. The scanned image itself is not touched. Pages that already have a text layer are skipped unless you ask otherwise.
Compared with upload-based tools: Online OCR services upload the scan to their servers, and free tiers cap pages or files a day. Scans are often the documents people least want copied: IDs, signed contracts, bank and medical letters. Here the reading happens on your device, with no page limit, and the output is your own PDF with a text layer rather than a Word file that loses the layout.
Verify it yourself. Give the page a short while after your first run to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
How do I know if my PDF needs this?
Try to select a word with the mouse. If you get a box around the whole page, or nothing at all, the page is an image and needs OCR. If single words highlight, it already has text.
Will the pages look different?
No. The scanned image is not touched; the text is added in a layer that is never drawn, the same way Acrobat’s Recognize Text does it.
Will the file get bigger?
Only a little. The added text is tiny next to the scanned images, and the images themselves are copied as they are, not recompressed. If the scan was already too large to email, run it through Compress PDF afterwards.
Is the lease or contract uploaded?
No. Every page is rendered and read in this tab, on your device.
More PDF tools
OCR PDF
Text recognition for scanned pages, run on your own device: the PDF looks the same, but now you can search it and copy from it.
JSON ↔ CSV
Paste or drop your data, choose a direction and get a table or an array back. What you paste stays on this device.
Merge PDF
Combine PDFs into one document and set the order with the arrows. No watermark, nothing uploaded, and the size limit is your device’s memory (phones hold less).
Split PDF
Pull out the pages you need, or break a document into single pages. Done on your device.
Other conversions
Guides
- How to make a scanned PDF searchableA scan is a photograph of paper, not text, which is why you cannot search it. Here is how OCR adds a text layer, and a free browser tool for it.