How to make a PDF searchable (OCR) on your phone
A scanned PDF is often just a picture of a page. You can read it, but you can’t search it or copy text from it. OCR (optical character recognition) fixes that by reading the text and adding it to the PDF. Here’s how to do it well on your phone.
In short
- A searchable PDF keeps the page image and adds an invisible layer of text.
- To test any PDF, search it for a word you can see on the page.
- Good light and a flat page matter more than which app you use.
- Always check names, dates and amounts. OCR isn’t perfect.
What a searchable PDF is
When OCR runs, the app recognizes the letters in the page image and places the text, invisibly, in the same spot on the page. The PDF looks exactly the same, but now you can search it, select and copy its text, and find the file later by a word inside it. It’s also more accessible: screen readers can read the text aloud.
Step 1: Check whether your PDF is already searchable
Open the PDF in a viewer that has a search or find option, and search for a word you can see on the page. Or press and hold on a word to select it. If the search finds the word, the PDF already has text. If nothing can be found or selected, it’s an image-only PDF and needs OCR.
Step 2: Start with a clean image
OCR accuracy depends mostly on the picture it reads. If you’re scanning the page yourself:
- Lay the page flat in even light, without shadows from your hand or phone. Daylight near a window works well.
- Hold the phone straight above the page and let the page fill most of the frame.
- Use a scanner mode that crops and straightens the page, rather than a plain photo.
- For text documents, a black-and-white or high-contrast setting often helps.
- Retake blurry pages. Zoom in on small print before you accept the scan.
Step 3: Run OCR and save as a PDF
You have a few options, depending on what you need and how private the document is:
- A scanner app with on-device OCR. Many document scanner apps can import an existing PDF or photo and recognize its text. Look for wording like “text recognition”, “OCR” or “make searchable”, and check that the app says it reads text on the phone rather than on its servers.
- Copy the text only. If you just need the words, not a PDF, the iPhone’s Live Text lets you select text in photos and in the camera view. On Android, Google Lens can copy text from an image.
- Cloud services. Some online tools and cloud storage apps run OCR for you. They work, but your document is uploaded to do it, which may not suit tax, medical or ID documents.
- On a computer. The free, open-source tool OCRmyPDF adds a text layer to scanned PDFs on your own computer, with nothing uploaded.
Step 4: Check the result
Search the finished PDF for a few words, especially names, dates and amounts. Common problems to watch for:
- Look-alike characters. OCR can confuse 0 and O, 1 and l, or 5 and S. Numbers matter most on receipts and bills.
- Handwriting. Printed text is recognized far more reliably than handwriting.
- Columns and tables. Search may work fine, but copied text can come out in an odd order.
- Language. If the app asks, choose the document’s language so accented letters like é, è and ç come out right.
- Faint print. Faded receipts and small print may need a rescan with better light or more contrast.
Keep the file a sensible size
Phone cameras take large photos. A good scanner saves pages at a resolution that keeps text sharp without making the file huge. If a few pages come out very large, check your scanner’s quality setting. Very large files are slow to share, and email or upload forms may refuse them.
A private OCR app: Cloora
We make Cloora, a document scanner that reads the text on every page on your phone and saves small PDFs you can search and copy text from. You can also import photos and existing PDFs and make them searchable, then search all your documents by any word printed inside them. Cloora reads printed English, French and other languages written in the Latin alphabet, and text recognition is part of its free features.
Cloora is coming soon to Google Play and the App Store. Learn more about Cloora
Questions
Does making a PDF searchable change how it looks?
No. The text layer is invisible and sits behind the page image, so the page looks the same. You simply gain the ability to search, select and copy the text.
Can OCR read handwriting?
Results vary a lot. Neat printing is sometimes recognized, but cursive and quick notes often aren’t. OCR works best on printed text, so check handwritten pages carefully.
How can I tell if a PDF already has text?
Search it for a word you can see on the page, or try to select a word. If the search finds it, the PDF already has a text layer.