Highlight Text in PDF Online, Free

Highlight any passage in a PDF — great for studying, proofreading, or flagging key clauses in contracts. Pick a color, drag across the text, done.

Highlight a PDF

Why Konomic

Multi-color palette

Yellow, green, pink, blue, and orange — assign colors per topic or priority.

Smart text selection

Drag across words and Konomic snaps to the text baseline for clean, professional-looking highlights.

Readable everywhere

Highlights save as standard PDF markup, visible in Acrobat, Preview, and every major reader.

No signup

Highlight, download, done — no account, no watermark, truly free.

How it works

  1. 1Open the PDF in Konomic
  2. 2Pick a highlight color from the toolbar
  3. 3Drag across the text to highlight
  4. 4Download the highlighted PDF

Frequently asked questions

Can I highlight scanned PDFs?

For scanned PDFs run OCR first so the text becomes selectable, then highlight works normally. Konomic has a free OCR tool.

Can I remove a highlight later?

Yes. Reopen the PDF in Konomic and click the highlight to delete it. Each highlight is a separate, editable object.

Do highlights print?

Yes. They print exactly as they appear on screen, in the color you chose.

Is there a page limit?

No. Highlight documents up to 50 MB on the free plan — hundreds of pages if needed.

Is my PDF private?

Yes. All files are HTTPS-encrypted in transit and deleted from our servers within 1 hour.