Extract Highlights & Comments from PDF
Pull every highlight and comment out of an annotated PDF, grouped by page or colour.
What was found
What to export
Result
About the Extract Highlights & Comments from PDF
An annotated PDF keeps your highlights, underlines and comments as annotations on top of the pages. This tool reads them all and gives you a tidy list: the text each highlight covers, the comment attached to it, the page, the colour, who wrote it and when. Replies to a comment stay together with it.
Export the list as Markdown for a notes app, as plain text, or as CSV for a spreadsheet. Group it by page, or by colour when the colours mean something (yellow for key points, green for things to check). The file is read in your browser and never uploaded.
How to use it
- Choose the annotated PDF or drag it onto the box. Every page is read; a password-protected file asks for its password first.
- Tick the kinds of annotation to export — highlights, underlines, strike-outs, sticky notes, free-text comments, ink notes — and pick an author if several people commented.
- Choose Page or Colour grouping, decide whether to include author, date and colour, and pick Markdown, plain text or CSV.
- Check the preview, then press Download or Copy.
Examples
## Page 3 > The committee shall meet at least twice a year. *Highlight · Yellow · Ann Lee · 2024-01-02 09:30* Check this against the current rules. - **Reply** (Bo Chen, 2024-01-03 10:15): Agreed, see section 4.
The quote is the text under the highlight, the italic line says what, in which colour, by whom and when, and the paragraph is the comment attached to it. Author, date and colour can be left out.
No.,Page,Type,Colour,Colour code,Text,Comment,Author,Date,Reply to 1,3,Highlight,Yellow,#ffff00,The committee shall meet at least twice a year.,Check this against the current rules.,Ann Lee,2024-01-02 09:30, 2,3,Sticky note,,,,"Agreed, see section 4.",Bo Chen,2024-01-03 10:15,1
A reply is its own row; “Reply to” holds the number of the row it answers.
Common uses
- Turning the highlights you made while reading a paper or book into notes for your notes app.
- Collecting the review comments from a contract, report or manuscript into one list to work through.
- Sending a reviewer’s comments to someone who does not have the marked-up PDF.
- Sorting highlights by colour, when each colour stands for a topic or a kind of point.
- Checking what comments and markup a PDF still contains before you share it.
How the text under a highlight is found
A highlight, underline, strike-out or squiggly underline stores the rectangles it covers (its QuadPoints, ISO 32000-1 §12.5.6.10) but not the words. The tool reads the exact position of every character on the page and takes the characters whose centre lies inside those rectangles, in reading order. A highlight over two lines gives two pieces, joined with a space; a word hyphenated at the end of a line is joined up if you leave that option on.
Text on scanned pages that have an invisible OCR layer works the same way. On a scan without a text layer there are no characters to find — the highlight is still listed, with a note, and PDF OCR can add the text layer first.
What counts as an annotation
Only markup saved as annotations is found: the marks made with the highlight, underline, note, text-box and pen tools of PDF readers such as Acrobat, Preview, Foxit or Edge, once the reader has saved them into the PDF. Markup that was flattened (printed to PDF, or burned in) is part of the page picture and cannot be extracted. Stamps, lines, shapes and carets are listed when they carry a comment. Links, form fields and the pop-up windows of notes are not comments and are left out.
Replies and review states
When a reader lets you reply to a comment, the reply is stored as its own annotation that points to the one it answers. Here all replies are grouped under the first comment of the thread, oldest first. A review state such as “Accepted” or “Rejected” set on a comment is shown as a reply.
Sources
- ISO 32000-1:2008, Document management — Portable document format — Part 1: PDF 1.7, §12.5.6.10, Text markup annotations: highlights, underlines, strike-outs and squiggly underlines and their QuadPoints.
Limitations
- Only annotations stored in the PDF are found. Highlights kept in a reading app’s own library, or burned into the page, are not in the file.
- The text comes from the page’s text layer. A highlight on a scan with no text layer shows no text — the summary counts them.
- A highlight that cuts through a letter keeps the characters whose centre is inside it, so the first or last letter of a partly covered word can be missing.
- Colours are those stored in the file; readers draw highlights with some transparency, so a colour can look lighter on screen. Names such as Yellow or Green are approximate.
- Annotations marked hidden in the file are skipped. Dates are shown as the file wrote them, without converting time zones.
- Text in a right-to-left or vertical script is taken in the order the file draws it, which can differ from reading order.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
Is my PDF uploaded?
No. The file is opened and read by your browser on your device, and the Markdown, text and CSV are made there. Nothing is sent to MySmartCoPilot or anyone else.
Why is the text under a highlight missing?
The page probably has no text layer — it is a scan — or the highlight sits on a picture. The highlight itself is still listed. Run the file through PDF OCR to add the text layer, then extract again.
Does it work with highlights from Preview, Acrobat, Foxit or Zotero?
Yes for Preview, Acrobat and Foxit: they save highlights into the PDF as standard annotations. Zotero and many reading apps (on e-readers and tablets, for example) keep highlights in their own database instead; export a copy of the PDF with its annotations from the app first, and open that copy here.
What is the difference between the text and the comment?
The text is what the highlight covers in the document. The comment is what the reader typed into the note attached to the highlight, or the text of a sticky note or free-text box.
Can I remove the comments from a PDF with this?
No, this tool only reads. To remove comments before sharing a file, use PDF Sanitizer or Flatten PDF.