Highlight PDF - Free Online Browser Tool

Apply yellow, green, or red translucent highlights to pages.

Markup annotations are what make a PDF reviewable: reviewers highlight, underline and strike through, and the markup travels inside the file. This tool applies translucent highlight marks to the pages you specify, in the colour reviewers expect.

This highlight pdf utility runs completely inside your web browser. Your document is opened locally and processed on your own device using JavaScript and WebAssembly, so your file is never uploaded to any server. There is no signup, no watermark and no limit on how many documents you can handle.

  • 100% client-side - files never leave your device
  • Instant processing, no upload wait
  • Works on desktop, tablet and mobile
  • Free forever, no account required

Common next steps: Underline Text, Add Sticky Notes / Comments, Bulk Keyword Redaction, Strikethrough Text.

How to Use the Highlight PDF Tool

Four steps, and the whole thing runs locally on your own device.

  1. Load the document

    Drop in the PDF you want marked up.

  2. Choose the highlight colour

    Yellow is the reviewer’s default, with green and red available for different meanings such as agreement and objection.

  3. Select where to apply

    Mark whole pages, a page range, or a specific selection depending on how the markup is distributed.

  4. Apply and download

    Translucent highlights are drawn over the content, so the text remains fully readable underneath.

Frequently Asked Questions

Are these real annotation objects or just coloured rectangles?

Real highlight markup stored in the document, which is why it survives into other PDF readers and is attributed to your markup rather than being part of the page image.

Can I see the highlight in Adobe Acrobat too?

Yes. Standard highlight markup is interoperable, so it appears in Acrobat and other readers as a proper annotation.

Why is my highlighted text still readable?

Because the highlight is translucent by design. Reviewers need to read exactly what they are marking, so the mark sits over the text without hiding it.

Does highlighting change the file size much?

Very little. Markup is lightweight vector data, unlike rasterising the page.

How do I remove the highlights afterwards?

Run Flatten / Remove Annotations, which strips all markup from the document in one step.