How to OCR a PDF on Mac
Mac has excellent built-in tools for working with PDFs — Preview can annotate, sign, and even fill forms. But there's one thing Preview cannot do: make a scanned image-only PDF searchable. For that, you need OCR, and until recently that meant paying for Adobe Acrobat Pro or using a cloud service that uploads your documents to a remote server. LazyPDF's OCR tool changes that. It runs Tesseract.js — an open-source OCR engine — entirely inside Safari or Chrome on your Mac. Your scanned PDF is processed locally using your Mac's CPU, the text is embedded into the PDF, and you download a fully searchable document. No upload, no subscription, no third-party access to your files. This guide explains how to do it on Mac, how it compares to Preview and other Mac options, and tips for getting the best OCR accuracy.
Step-by-Step: OCR a Scanned PDF on Mac
The LazyPDF OCR tool works in both Safari and Chrome on macOS. You can drag your PDF directly from Finder into the browser tab, which is faster than using the file picker. The tool uses Tesseract.js running in a Web Worker, so it won't freeze Safari or Chrome while it processes your document — you can still use the browser normally (in other tabs) while OCR runs. Here is the complete workflow.
- 1Open Safari or Chrome on your Mac and go to lazy-pdf.com/en/ocr
- 2Drag your scanned PDF from Finder into the drop zone on the page, or click 'Choose File' and navigate to it using the macOS Open dialog
- 3From the language dropdown, select the language of the document — English is selected by default, but choosing the right language (French, German, Spanish, Japanese, etc.) significantly improves accuracy
- 4Click 'Run OCR' and wait for Tesseract.js to process the pages, then click 'Download PDF' to save the searchable PDF to your Downloads folder
How Mac's Preview Compares to Tesseract.js OCR
macOS Preview is a capable PDF tool but has no built-in OCR functionality. When you open a scanned PDF in Preview and try to select text, nothing is selectable because the pages are images. The macOS system does have its own Live Text feature (introduced in macOS Monterey) that can detect text in images — you'll notice a cursor change when hovering over text in Preview. However, Live Text does not embed that recognized text into the PDF file itself; it's only a display-layer recognition. For a truly searchable, standard PDF where the text is accessible to any PDF reader (not just Preview on macOS Monterey+), you need proper OCR that embeds a text layer — which LazyPDF provides.
Using macOS's Built-In Scanning and LazyPDF Together
Mac's Continuity Camera feature lets you use your iPhone as a document scanner directly from macOS. In any Finder window, right-click and choose 'Import from iPhone → Scan Document'. Your iPhone opens the scanner, you scan the document, and it appears as a PDF in the Finder window on your Mac. This gives you a high-quality scanned PDF — but it still won't be searchable. After the scan appears in Finder, drag it into the LazyPDF OCR tool in Safari or Chrome and run OCR. Within a couple of minutes, you have a fully searchable PDF without any third-party scanning app.
OCR Accuracy Tips for Mac Users
On Mac, you have more control over scan quality than on mobile. When scanning with a physical scanner, always scan at 300 DPI minimum — most PDF readers and scanners default to 200 DPI, which noticeably degrades OCR accuracy. Choose grayscale or black-and-white scanning mode for text documents rather than color — smaller file size, higher contrast, better results. If you're scanning with iPhone via Continuity Camera, the auto-enhancement is excellent. For old or faded documents, use Preview's Tools → Adjust Color to increase contrast before running OCR. Straighten any tilted pages using the LazyPDF Rotate tool before submitting to OCR — even a 2-3 degree tilt reduces Tesseract accuracy.
Searching and Using the OCR Result on Mac
After downloading the searchable PDF, you can verify it works immediately. Open the downloaded file in Preview and press Cmd+F — the search bar appears. Type any word from your document and Preview will highlight it if OCR succeeded. You can also select and copy text from the PDF in Preview, which is useful for quoting from documents or extracting data. In Safari or Chrome's PDF viewer, Cmd+F also works. For indexing, once the PDF has an embedded text layer, macOS Spotlight will index it — your document will appear in Spotlight search results (Cmd+Space) when you search for words contained in it. This makes filing scanned receipts, invoices, or research papers much more useful.
Frequently Asked Questions
Does macOS Preview do OCR on scanned PDFs?
Preview uses macOS Live Text to recognize text visually in images, but this does not create a searchable PDF — the text is only recognized as a display overlay in newer macOS versions and is not embedded into the file. Other PDF readers and search tools won't find the text. For a proper searchable PDF with an embedded text layer, use LazyPDF's OCR tool at lazy-pdf.com/en/ocr — it embeds OCR results into a standard PDF text layer that works everywhere.
Can I OCR PDFs on Mac for free without Adobe Acrobat?
Yes. LazyPDF's OCR tool at lazy-pdf.com/en/ocr is completely free and runs in Safari or Chrome on Mac. Tesseract.js does the character recognition locally on your machine. Another free option is Tesseract OCR via Homebrew (a command-line tool for developers), but LazyPDF is much easier for non-technical users — it provides a browser interface, PDF output, and requires no installation.
Will Spotlight search work on a PDF after OCR on Mac?
Yes. After downloading the OCR-processed PDF from LazyPDF, macOS Spotlight will index the embedded text layer. Once Spotlight reindexes the file (typically within a few minutes of adding it to a Spotlight-indexed folder like Documents or Downloads), you can search for words from the document using Cmd+Space. This makes all your scanned receipts, contracts, and notes discoverable by name or content, which is one of the most practical benefits of OCR.