What is a redline?

A redline (sometimes called a blackline or a comparison) is a version of a document marked up to show how it differs from an earlier version. The name comes from the red ink once used to mark up printed drafts. Lawyers, procurement teams, landlords and anyone negotiating a document send redlines so the other side can see every proposed change without reading the whole text again.

A redline can be made in two ways: by hand while editing (Word’s Track Changes records edits as you make them) or by comparison (two finished versions are compared and the differences marked). Comparison is the safer of the two: it catches every difference, including edits made with tracking switched off.

The usual markings

Inserted text is underlined, usually in blue.
~~Deleted text~~ is struck through, usually in red.
Moved text is shown in green: struck through where it came from, double-underlined where it went.
Each change is often numbered, so a covering email can say “see change 14”.

RedlineKit uses exactly these conventions on screen, in the PDF redline and in the change list, with the change numbers in the margin.

How to redline a document from two versions

Find the two versions: the one you sent (or agreed) and the one you received. They can be Word files or PDFs, or one of each.
Drop them on Original and Revised above and press Compare.
Go through the changes in order with J and K. Click a change in the list to jump to it.
Export: the PDF redline to send round or file, and the Word version with tracked changes if the other side should accept or reject changes one by one.

Compare two files now Free on screen. Files stay on your device.

Redline, tracked changes or both?

A PDF redline is for reading: it can’t be edited by accident, it looks the same on every device and it prints well. Send it to people who need to approve or sign off, and keep it on file as the record of what changed in a round.

A tracked-changes Word file is for working: the reader can accept a change, reject it, or edit around it, and the document becomes the next draft. Send it to the person who will produce the next version. RedlineKit’s Word export starts from the revised file itself, so its styles, numbering and layout stay as they were; only the differences are marked. You can set the author name shown in Word’s Review pane before exporting.

Good habits when sending a redline

Compare against the last version the other side saw, not your own working draft, so the redline shows only what is new to them.
Don’t rely only on the other side’s tracked changes. Tracking can be switched off for an edit, and changes can be accepted before the file is sent. Comparing the two clean versions catches those.
Say what the redline covers. RedlineKit compares the body text, including tables and lists, but not headers, footers, footnotes, comments or formatting. If those matter, check them separately.
Name the files clearly. The PDF redline’s title and footer name both versions, so the reader knows what was compared with what.

Is it free?

Comparing and reading the redline on screen is free, with no sign-up and no limit. Exporting costs one credit per pair of documents (10 credits for £5, or 50 for £15), covering both the PDF and the Word file, downloaded as often as you need.

How to redline a document