PDF Highlighter
Search and highlight keywords, financial amounts, important clauses, or custom passages in PDF documents with vibrant fluorescent colors, adjustable transparency, and razor-sharp text preservation.
Upload contracts, research papers, reports, or study materials to highlight keywords, terms, or sections.
Document Loaded
Configure your highlighter ink color and keywords below.
Highlighter Ink & Keyword Settings
Balanced for vibrant color & text clarity
PDF Highlighted Successfully!
Translucent highlight annotations have been applied over your specified keywords.
How to Highlight Text in a PDF in 3 Steps
Highlight keywords, passages, and financial amounts with fluorescent colors in seconds.
Upload PDF Document
Drag & drop your PDF contract, invoice, syllabus, or paper into the uploader.
Choose Words & Colors
Enter the terms, names, or numbers you want to mark and pick from 6 fluorescent colors (yellow, mint, pink, cyan, lavender, peach).
Download Annotated PDF
Download your finished PDF. All original vector text, links, and bookmark navigation remain 100% intact.
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Crop custom rectangular regions, diagrams, charts, or embedded photos and export to PNG, JPG, or WebP.
Word & Character Counter
Instant word, character, sentence, and paragraph counting with reading time metrics & audit report.
PDF Contrast & Scan Enhancer
Darken faint text, whiten muddy scanned backgrounds, and boost contrast on scanned documents & receipts.
Why Use Our PDF Highlighter Tool?
Instant Keyword Search & Highlight
Automatically scans multi-page documents and highlights all matching phrases, monetary figures, dates, or clauses in one click.
6 Fluorescent Ink Colors
Organize your notes with color coding: Neon Yellow for key facts, Mint Green for definitions, Pink for urgent notices, and Cyan for citations.
Adjustable Transparency
Fine-tune opacity between 15% and 75% so underlying text and small numbers remain completely crisp, readable, and copyable.
Zero Rasterization
Unlike inferior tools that convert entire PDF pages into blurry JPEGs, our tool preserves native vector lines, embedded fonts, and searchability.
Target Specific Pages
Apply highlights across all pages, first page only, last page only, or custom page selections (e.g. 1, 3, 5-10).
100% Private & Auto-Purged
Files are processed in an encrypted sandbox and permanently deleted from our servers after 2 hours.
Frequently Asked Questions
How does the keyword highlighter locate text in my PDF? ▼
Our engine parses the internal Text Matrix (Tm) operators of the PDF stream to extract the exact coordinate positions of words on the page. It then renders a semi-transparent highlight layer directly over each match.
Can I highlight multiple different terms in one document? ▼
Yes! Enter as many keywords or phrases as you want, separated by commas or new lines (e.g. "Tax Invoice, $1,500, Payment Due, Approved"). The highlighter will find and mark all of them.
Will text under the highlight remain selectable and copyable? ▼
Yes. Because the tool does not flatten or rasterize your PDF pages, all text remains native vector characters that can be selected, searched, and copied in Adobe Acrobat, Apple Preview, and web browsers.
Can I highlight scanned PDFs without a text layer? ▼
For scanned document images that do not have selectable text, you can use our OCR PDF tool first to create a searchable text layer, or use the area mode to highlight rectangular regions directly.