Tiny Online Tools
Highlight Text in PDF — Free & Private
Whether you're marking up a contract, preparing study notes, or reviewing a research paper, our free online PDF highlighter automatically draws colored translucent overlays over every occurrence of the words you choose. No uploads, no sign-up, and no limits — the entire process runs inside your browser.
How to use it
- Select a PDF — drag it in or click to browse.
- Enter the words or phrases you want highlighted. Use commas to separate multiple terms (
total, amount due, invoice). - Optionally enable case-sensitive matching.
- Pick a highlight color — yellow, green, pink, blue, or orange.
- Click Highlight matches. Every occurrence is located, and a translucent rectangle is drawn over it. The summary shows how many matches were found.
- Download the highlighted PDF — the original text remains fully selectable and searchable underneath.
Why automatic highlighting?
- Speed — hundreds of occurrences are marked in one pass, no manual clicking.
- Consistency — every match gets the same color at the same size.
- Review workflows — share a reviewed copy with colleagues in seconds.
- Studying — mark every mention of a key term across a long textbook.
- Compliance & auditing — visually track which documents mention specific clauses.
Tips for best results
- Highlighting works on text-based PDFs — scanned images need OCR first (try our PDF to Text for quick text extraction).
- Translucent overlays let the underlying text stay readable and selectable.
- Use multiple terms to highlight synonyms or variations in one pass.
- Case-sensitive mode is useful when the term also appears as a prefix (
APIvs.api).
Privacy
All processing happens locally in your browser. No part of the PDF is ever sent to a server. Nothing is stored.
Related tools
- PDF Redactor — hide sensitive information with opaque boxes.
- PDF to Text — extract text from a PDF.
- Watermark PDF — add a watermark layer.