# Compare Documents in ChatGPT

> Ask ChatGPT to compare two versions of a document and get back a true redline from Version Story: every change marked up in a PDF or a Word file with tracked changes.

## Overview

By default, ChatGPT compares two documents by reading both and describing what it thinks changed. That is a summary, and it can leave changes out. With the Version Story plugin installed, ChatGPT hands the two versions to Version Story's comparison engine and gives you back the redline itself: every insertion, deletion, and move, marked up in the document.

The comparison is produced by Version Story, not written by ChatGPT, so the same two versions always give the same redline.

## Before you start

You need a Version Story account and the Version Story plugin, which is in ChatGPT's plugin directory. [Set Up the Version Story ChatGPT Redlining Plugin](/help/install-version-story-in-chatgpt) walks through it; it takes about a minute.

## Compare two versions

1. Start a chat with Version Story selected. Either click **Try in chat** on the plugin's page, or open the **Plugins** menu below the message box and choose **Version Story**.
2. Attach the two versions of the document.
3. Ask for the comparison, naming which version is the original:

   ```
   Compare these documents and give me a redline. The first file is the original.
   ```

ChatGPT sends both versions to Version Story and replies with two links: one to download the redline, and one to open the interactive redline in Version Story. If you ask what changed, it also summarizes the changes, working from the redline.

## Choose the format of the redline

You get a PDF redline unless you ask for something else. To get a Word document with tracked changes, ask for it by name: "Give me the redline as a Word document with tracked changes."

## Merge edits and trace versions

The plugin does more than compare two drafts:

- [Merge Edits in ChatGPT](/help/merge-edits-in-chatgpt): combine the copies several people edited into one Word document, with each person's changes tracked.
- [Trace Changes Across Drafts in ChatGPT](/help/trace-changes-in-chatgpt): see which draft in a series introduced each change.

## Where your comparisons are saved

Every comparison you run from ChatGPT is saved to a project in your Version Story account, next to the versions you uploaded. You can open it later at [app.versionstory.com](https://app.versionstory.com/login) without going back to the chat.

## Related

- [Compare Documents in Claude](/help/compare-documents-in-claude)
- [Get a Word File with Tracked Changes](/help/get-tracked-changes-word-file)