Highlight a Scanned PDF
Scanned PDFs are where most highlighters fall over. A page scanned from paper is really just an image, so there is no text to select and tools that highlight by text simply do nothing when you drag across it. FixTools sidesteps that entirely because it highlights by position, not by text. You upload the scanned file, see each page in the preview exactly as it was scanned, and click to drop a colored box wherever you want it. Drag it over the printed line, size it to fit, and pick yellow, red, blue, or green. Because the highlight is placed by coordinates rather than by selecting characters, it works the same on a crisp digital PDF and a slightly crooked scan of a contract or an old article. When every mark is placed, the file uploads over an encrypted connection, the highlights are drawn onto the pages, and the marked PDF downloads back to you. The uploaded copy is deleted after processing.
- Cost
- Free tier
- Sign-up
- Not required
- Processing
- Tool-specific
- Privacy
- Clearly disclosed
Works on image-based pages with no selectable text
Places highlights by position, not by text selection
Handles scans, faxes, and flattened exports
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
Why position-based highlighting works on scans
When you scan a paper document, the result is a picture of the page. There are no characters underneath for a tool to select, which is why text-based highlighters in many readers do nothing on a scan and can leave you thinking the file is broken. It is not broken, it just has no text layer.
FixTools draws each highlight as a colored box at the exact coordinates you choose, so it never needs to find text at all. That means it treats a scanned page the same as a native one: you point at where the printed words are, place the box, and the color lands there. If you also need the scan to be searchable, you can run it through OCR separately, but for simply marking up the important lines, position-based highlighting is all you need.
How to use this tool
Upload the scanned PDF, then click a page in the preview to drop a highlight box over the printed text. Size it, choose a color, click Add Highlight, and download the marked scan.
How It Works
Step-by-step guide to highlight a scanned pdf:
- 1
Open the tool
Launch FixTools Highlight PDF in your browser. No account or install is needed.
- 2
Upload the scanned PDF
Choose the scanned or image-based document from your device.
- 3
Click over the printed text
Click the page in the preview to drop a highlight box, then drag it over the line you want to mark.
- 4
Size, color, and add it
Adjust the box to fit the text, pick a color, add an optional note, and click Add Highlight.
- 5
Download the marked scan
Process the file and download the highlighted PDF. The uploaded copy is deleted afterward.
Real-world examples
Common situations where this approach makes a real difference:
Scanned contract
A buyer highlights the payment terms on a scanned agreement that has no selectable text.
Archived article
A researcher marks key passages in a scanned journal article from a library archive.
Faxed form
An office worker highlights the fields to check on a faxed form saved as a PDF.
Photographed pages
A student highlights notes in a PDF built from phone photos of a book, where no text exists to select.
Pro tips
Get better results with these expert suggestions:
Zoom in on faint scans
Enlarge the preview so you can place the box accurately over text that scanned lightly.
Add OCR if you need search
Highlighting works without it, but run OCR separately if you also want to search or copy the text.
Optimize heavy scans first
Large image-based PDFs upload and preview faster after a pass through the optimizer.
Use color to sort findings
On a long scan, color-code so approvals and questions are easy to separate at a glance.
Frequently asked questions
Related guides
More use-case guides for the same tool:
Related tools
Other tools you might find useful:
OCR PDF
Add a searchable text layer to the scan if you also need to search it.
Make PDF Searchable
Turn a scanned document into searchable text.
Optimize PDF
Reduce the size of a heavy scanned file.
Highlight Multiple PDFs at Once
Highlight several PDFs in one batch. Upload the files, place your highlights, process them together, and download each result. Uploaded securely, deleted after.
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 in Different Colors
Highlight a PDF in yellow, red, blue, and green to color-code your markup. Place colored boxes on any page, add notes, and download the file free. No account.
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 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.
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.
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