OCR PDF
Recognize text in scanned PDFs and create searchable PDFs.
The two types of PDF
They look the same on the outside, but they’re very different inside:
- Digital (native) PDF: Created by a program, such as Word, a banking system, or an invoicing tool. The letters are actual text, so you can select, copy, search with Ctrl+F, and the file is usually small.
- Scanned (image) PDF: Created from a scanner or photos. Each page is an image. The computer “sees” pixels, not letters.
There’s also a third type: a scanned PDF with OCR. The image is still there, but an invisible text layer lets you search and copy text.
Three tests that take 10 seconds
- Select: Click and drag over a sentence. If the letters highlight blue one by one, the PDF contains text. If you see a rectangle over the whole page, or nothing happens, it’s an image.
- Search: Press Ctrl+F (on Mac, Cmd+F) and search for a word you can see. No results means it’s an image without OCR.
- Zoom in: Zoom in a lot. Digital text stays sharp at any magnification; a scanned page looks jagged and may show marks from the paper.
On a phone, tap and hold a word. If you see an option to copy it and selection handles appear, the PDF contains text.
Why it matters
- Copying and converting: Word or Excel converters need text. With a scanned PDF, they return only images. That’s the most common reason people say, “I converted it, but everything came out as an image.”
- Searching: Without OCR, finding a name in a 300-page scanned document means reading every page.
- File size: Scanned PDFs are much larger. A 10-page digital contract might be just a few hundred KB; a color scan can exceed 10 MB. Compression works well on scanned PDFs because it reduces the images.
- Accessibility: Screen readers used by people who are blind can’t read PDFs that contain only images.
- Official systems: Some document submission systems require searchable PDFs. Check the recipient’s instructions.
How to make a scanned PDF searchable
- Open OCR PDF and select the scanned file (or photos of the pages).
- Choose the document’s language and what you want to create: a searchable PDF, text, or both.
- Click Recognize text. The first time, the language model downloads and is saved in your browser.
- Download the result and try searching again.
If your PDF is already digital and you just want plain text without formatting, use PDF to text for instant results. If your scanned PDF is too large, Compress PDF reduces the page images.
Tips for better OCR
- Scan in good lighting, keep the paper flat, and avoid shadows from your hand or phone.
- Skewed documents or gray backgrounds lead to more errors. Straightening and brightening the image first can help a lot.
- Check numbers, tax IDs, and amounts carefully: mistakes here can be costly. OCR can confuse 0 with O and 1 with l.
- Handwriting and very small text are hard for any tool to recognize.
What if a digital PDF behaves like an image?
Sometimes the selection test works, but copied text comes out as a string of meaningless symbols. This can happen when the software that created the PDF embedded fonts with a custom encoding: the letters look right on screen, but the computer can't tell which characters the shapes represent.
In practice, treat this file like a scanned document. Run it through OCR, which reads the letter shapes much like a person would, then work with the recognized text. The same goes for PDFs that a system has "printed as an image" to prevent copying.
Frequently asked questions
My PDF has some pages with text and others that are scanned. Is that okay?
Yes, this is common in case files and document collections assembled from different sources. OCR works page by page and only adds text where it’s actually missing.
Does OCR change how the document looks?
In a searchable PDF, the original image stays visible. The recognized text sits in an invisible layer behind it, where it's used for searching and copying.
Why does search work, but copied text comes out strange?
The OCR may have been run at low quality, or the PDF may use fonts with an unusual encoding. Run OCR again from a better scan, or paste the output as plain text and review it.
Does scanning with a phone automatically create a searchable PDF?
It depends on the app. Some phone scanner apps run OCR automatically; others just save the image as a PDF. Use the search test to check the file you received.