How to Make a Scanned PDF Searchable with OCR (Free, Online)
A scanned PDF looks like a document, but it is really a stack of pictures. You cannot search it, select a word or copy a paragraph, because the computer sees an image, not letters. OCR (optical character recognition) reads the text in those images and adds a hidden layer of real text on top, so the document becomes searchable.
Do you need OCR? A 10-second test
Open the PDF and try to select a single word with your mouse.
| What happens | What it means | What to do |
|---|---|---|
| You can highlight individual words | The PDF already has real text | You do not need OCR |
| You can only select the whole page or nothing | The page is an image (a scan) | Use OCR |
Running OCR on a PDF that already has real text is not useful: it can make the file larger and the text slightly less sharp.
How to make a scanned PDF searchable
- Open the OCR PDF tool and add your scanned file.
- Choose the language of the document. This makes recognition much more accurate. You can pick more than one if the document mixes languages.
- Leave the mode on "Only read scanned pages", which skips any page that already contains text.
- Press the OCR PDF button and download the searchable PDF.
The result looks exactly like your original, but you can now search it, select words and copy text.
Choosing the right mode
- Only read scanned pages (recommended): pages that already have text are left alone. This is the right choice for almost every file.
- Re-read every page: use this only if the file is a scan and its existing text layer is wrong or missing. It is slower and can make the file larger.
Tips for better OCR results
- Scan at a good resolution. 200 to 300 dpi is the sweet spot for text.
- Keep pages straight. Tilted or skewed pages reduce accuracy. You can fix sideways pages first with Rotate PDF.
- Use good lighting when photographing pages with a phone, and avoid shadows.
- Pick the right language. Using the wrong language is the most common reason for bad results.
- Check important text. OCR can mistake similar characters, such as 0 and O, so review numbers and names.
There is a page limit
OCR is a heavy task, so each file has a maximum number of pages. If your document is longer, split the PDF into parts, run OCR on each, and merge the results.
What to do after OCR
- Convert to Word to edit the text: PDF to Word, see our guide.
- Make the file smaller with Compress PDF.
- Summarise a long scanned report with the AI Summarizer, which needs real text and works well after OCR.
Is my file safe?
Your file is encrypted in transit and at rest and deleted automatically, by default within 2 hours. We do not read it or use it to train AI. See the privacy page.
Frequently asked questions
How do I know if my PDF needs OCR?
Try to select a word with your mouse. If you cannot highlight individual words, the page is an image and OCR will help. If you can, it already has real text.
Why is the OCR result larger than my original?
OCR adds a text layer to the file, and re-reading every page can also re-encode the images. Use the default mode and only run it on real scans.
Does OCR change how my document looks?
No. It adds an invisible text layer on top of the page images, so the pages look the same but you can now search, select and copy the text.
How accurate is OCR?
Clear, straight, well-lit scans give the best results. Blurry, tilted or low-resolution pages lose accuracy, so always check important text.