SunPDF

Highlight a PDF online for free

Highlight text in your PDF, then choose the highlight color and opacity.

Use this tool for free as often as you need. The document is processed on your device so its contents remain under your control.

or drop the file herePDF · Up to 50 MB per file

How it works

  1. Open the PDF you want to review.
  2. Select text and turn on highlighting.
  3. Check the contrast and export.

What you can do

  • Highlight an editable text block
  • Choose color and opacity
  • Combine highlights with other corrections

See the tool in action

Highlight a PDF, SunPDF
Real SunPDF screenshot for “Highlight a PDF”, created with a fictional practice document containing no personal data.

Try the example

Fictional documents: three practice pages and an appendix, with no personal data.

Page 1: select the date text and enable its highlight style. Check contrast and the exported highlight color.

What does this PDF tool do?

Choose the highlight color and opacity, then continue working on the document. The result is included in the exported copy.

Document processing happens in your browser. SunPDF does not upload your PDF to a server for editing. Closing or refreshing the tab ends the current session.

When to use this tool

Highlighting helps with review or reference when the words in the PDF can be selected as text.

How to check the result

Make sure the colour remains readable on screen and in print, and that only the intended lines are highlighted.

Continue with another tool

Edit PDF textAdd shapes to a PDFAdd text to a PDFAdd a checkmark to a PDF

Guides for this tool

Follow the steps and checks to make before saving your document.