Highlight a PDF on Mac
Preview on the Mac can highlight text, but only when the PDF has a clean, selectable text layer, and its highlighter snaps to whatever words it thinks you meant rather than the exact span you want. On scanned pages, forms, or oddly encoded files it simply refuses. FixTools takes a different approach that works regardless of how the PDF was made. You open the tool in Safari, Chrome, or any browser, upload the file, and each page renders so you can see the layout precisely. Click where you want to mark, drag a highlight box to the exact size you need, and pick from yellow, red, blue, or green. Add a note if you want to remember the reason. Once everything is placed, the file uploads over an encrypted connection, the highlights are drawn into the pages on the server, and the finished PDF downloads to your Mac. The uploaded copy is deleted after processing, and nothing needs installing.
- Cost
- Free tier
- Sign-up
- Not required
- Processing
- Tool-specific
- Privacy
- Clearly disclosed
Runs in any Mac browser, no install and no Preview limits
Click and drag boxes to the exact size you want
Works even when Preview refuses to highlight the file
PDF Tool
Highlight PDF
Open the tool to see its processing method, supported formats, and current limits.
🚀Open Highlight PDFFree tier · No account · Limits shown before processing
When Preview will not highlight and this will
Preview relies on the PDF having a usable text layer. A page scanned from paper, a file exported flat from design software, or a form with unusual encoding often has no selectable text, so the highlighter does nothing when you drag across it. That is a common and frustrating wall to hit right when you need to mark something up.
FixTools does not depend on selectable text. You place a colored box by hand at the position and size you choose, so it works on scanned pages and image-based PDFs just as well as on clean digital ones. The tradeoff is that you position each highlight yourself rather than having it snap to words, which is exactly what you want when the automatic highlighter would otherwise give up entirely.
How to use this tool
Open the Highlight PDF tool in your Mac browser, upload the PDF, and click the page to drop a highlight box. Drag it to size, choose a color, click Add Highlight, then download the finished file.
How It Works
Step-by-step guide to highlight a pdf on mac:
- 1
Open the tool in your browser
Launch FixTools Highlight PDF in Safari, Chrome, or Firefox on the Mac. There is nothing to install.
- 2
Upload the PDF
Drag the file into the upload area or click to choose it from Finder.
- 3
Click to place a highlight
Click the page in the preview to drop a box, then drag its edges to cover exactly the text you mean.
- 4
Pick a color and note
Choose yellow, red, blue, or green, add an optional note, and click Add Highlight. Repeat across pages.
- 5
Download the highlighted PDF
Click process. The finished file downloads to your Mac and the uploaded copy is deleted.
Real-world examples
Common situations where this approach makes a real difference:
Scanned document
A researcher highlights passages in a scanned journal article that Preview will not let them select.
Precise span
An editor marks the exact half-line that matters instead of Preview snapping to the whole sentence.
Locked-down Mac
An employee on a managed Mac who cannot install Acrobat highlights a report in the browser instead.
Consistent color-coding
A reviewer uses the same four colors across every document for a repeatable markup system.
Pro tips
Get better results with these expert suggestions:
Resize with the width and height fields
After dropping a box you can type exact width and height values for pixel-consistent highlights across pages.
Use the page jump box
Type a page number to jump straight to it in a long PDF instead of clicking through every page.
Keep the original
Save your source PDF separately so you can re-mark it cleanly if you change your mind.
Pair with Optimize PDF
Run a heavy scanned file through the optimizer first so the preview and upload are quicker.
Frequently asked questions
Related guides
More use-case guides for the same tool:
Related tools
Other tools you might find useful:
Optimize PDF
Clean up and lighten the document before or after marking it.
Add Comments to PDF
Attach written notes alongside your highlights.
PDF Merger
Merge separate PDFs into one before highlighting.
Highlight a PDF Online, Free
Highlight a PDF online free with no account. Drop colored highlight boxes on any page, add notes, and download the file. Uploaded securely, deleted after use.
Highlight a PDF on Android
Highlight a PDF on Android in Chrome for free. Drop colored highlight boxes on any page, add notes, and download the marked file. No app to install needed.
Highlight a PDF Without Adobe
Highlight a PDF without Adobe Acrobat or an account. Drop colored highlight boxes in the browser and download the marked file free. No install, works on any OS.
Highlight a PDF on iPhone
Highlight a PDF on iPhone in Safari for free. Tap to drop colored highlight boxes on any page, add a note, and download. No app to install, works in Safari.
Highlight a PDF for Studying
Highlight lecture notes and textbook PDFs for studying, free. Color-code key points in yellow, red, blue, and green, add notes, and download a revision copy.
Highlight a PDF for Contract Review
Highlight a contract PDF for review. Flag clauses in color, add notes, and download the marked file. Uploaded over an encrypted connection, then deleted.
Ready to get started?
Open Highlight PDF to review its free limits and processing method.
Open Highlight PDF →Free tier · No account needed · Transparent limits