PDF Underline / Strikethrough
Upload a PDF and draw underline or strikethrough markup directly on any page. Choose from 6 line colors, switch between markup types per annotation, and annotate across multiple pages - all processed locally in your browser with no server upload.
Upload a PDF to start adding markup.
Why Use Our PDF Underline / Strikethrough Tool?
Draw Underline & Strikethrough
Select any text region by dragging on the live page preview to apply underline or strikethrough marks with pixel-perfect placement.
6 Line Colors
Choose from Black, Red, Blue, Green, Orange, or Purple so your markup always stands out against any background color.
Underline or Strikethrough - Your Choice
Switch between markup types per annotation. Underlines draw at the bottom edge of your selection; strikethroughs draw across the vertical center.
Private Browser Processing
All processing runs locally in your browser - your PDF never leaves your device and no server upload is required.
Common Use Cases for PDF Underline / Strikethrough
Contract Review
Underline key terms and strike through outdated clauses in contracts so reviewers immediately see what changed without editing the source document.
Academic Proofreading
Mark up thesis drafts and academic papers with underlines for emphasis and strikethroughs for text that needs to be removed in the next revision.
Legal Document Annotation
Use strikethrough markup to flag removed provisions and underlines to highlight critical references in legal briefs and court filings.
Business Report Feedback
Mark up quarterly reports and proposals by underlining figures that need follow-up and striking through projections that are no longer valid.
Study Notes & Textbooks
Underline definitions and key concepts in PDF study guides, or strike through topics you have already mastered to track revision progress.
Editing Manuscripts
Apply strikethrough markup to draft passages scheduled for deletion and underlines to phrases that need rewording - all without altering the original text layer.
Understanding PDF Underline and Strikethrough Markup
What is PDF Text Markup?
PDF underline and strikethrough markup are visual overlays placed on top of existing PDF text to communicate editorial intent without modifying the underlying content. An underline draws a horizontal line beneath selected text - used for emphasis, key terms, or items requiring attention. A strikethrough draws a horizontal line through the vertical center of selected text - used to indicate deleted, outdated, or rejected content. Our PDF text markup tool renders these lines directly on the page using pdf-lib, entirely in your browser, so no server upload is ever required.
How Our PDF Underline / Strikethrough Tool Works
- Upload your PDF - drag and drop or click to browse. The file is parsed locally and the first page renders in the interactive editor.
- Select markup type and color - choose Underline or Strikethrough from the toolbar, then pick one of 6 line colors. Each annotation can have its own type and color.
- Draw annotations by dragging - click and drag over any text region on the canvas preview. Release to place the annotation. Use the page sidebar to switch pages and annotate anywhere in the document.
- Download the annotated PDF - click Download to apply all markup to the pdf-lib document and save the result. Lines are rendered as permanent vector content layered on top of the original page.
How Underline and Strikethrough Lines Are Positioned
- Underline - the line is drawn at the bottom edge of your drag selection, spanning the full width of the selected region.
- Strikethrough - the line is drawn at the vertical midpoint of your drag selection, spanning the full width of the selected region.
- Line thickness - scales proportionally with the height of your selection so markup stays readable at any font size.
- Coordinate mapping - screen pixel coordinates are converted to PDF points using the render scale factor, so the lines land in the correct position after download.
Privacy, Security & Availability
Our PDF underline / strikethrough tool processes your files entirely inside your browser using the pdf-lib library. Your PDF is never uploaded to any server, shared with third parties, or stored anywhere outside your device. The tool is 100% free, requires no account or sign-up, and works on all modern browsers across desktop and mobile.
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Frequently Asked Questions About PDF Underline / Strikethrough
Upload your PDF, then select "Underline" or "Strikethrough" from the markup type selector. Click and drag over the text you want to mark on the page preview. Release to place the annotation. When you are done, click Download to save the annotated PDF.
Yes. Each annotation has its own type. You can switch between Underline and Strikethrough at any time while editing, and each annotation remembers the type you selected when you drew it.
Yes. Use the page thumbnail sidebar to navigate to any page in your PDF and draw annotations there. Markups from all pages are applied together when you click Download.
Hover over any annotation in the canvas preview to reveal a delete button, or click the trash icon next to it in the annotations list on the right panel. The "Clear Page" button removes all annotations from the current page, and "Clear All" removes every annotation across the document.
No. The tool draws lines as new vector content on top of the page canvas - the original text, images, and formatting in your PDF are completely untouched. This is a non-destructive overlay approach.
No. All processing happens locally in your browser using the pdf-lib library. Your file never leaves your device, ensuring complete privacy even for sensitive documents.
Yes, completely free with no registration, email sign-up, or usage limits. You can annotate as many PDFs as you need at no cost.
Yes. Select your preferred color from the color picker before drawing each annotation. Choose from Black, Red, Blue, Green, Orange, or Purple. Each annotation retains the color that was active when you drew it.