How to summarize long email threads

What a useful thread summary contains

A thread summary isn't a shorter version of every message. It answers four questions: what was decided, what's still open, who owns each open item, and what, if anything, is being asked of you. If a summary doesn't tell you whether you need to reply, it hasn't done the job. More on the concept in email summarization.

Summarize a thread in Gmail with Gemini

Gmail can summarize a conversation at the top of the thread. Google calls these AI Overview conversation summaries, and they need Gmail's smart features turned on. They're available in some languages only.

1. 1
   Open the thread on your computer

   Open the conversation in Gmail on the web. On long threads, Gmail may show a summary card at the top automatically.

2. 2
   Click Summarize this email

   If no summary is showing, click Summarize this email at the top of the thread. The overview lists the key points and replies. Click the up arrow to hide it again.

3. 3
   Act on suggested reminders

   If the summary spots a task with a due date, it can show a Remind me option next to it. Click it to create a reminder.

4. 4
   Ask follow-up questions in the side panel

   On an eligible Google Workspace or Google AI plan, click Ask Gemini at the top right and ask something specific, like "What did Priya agree to on pricing?"

If you see an error in the summary, click Bad suggestion below the card. That feedback goes to Google, and it's also a reminder that the card can be wrong.

Summarize a thread in Outlook with Copilot

Copilot can summarize threads in new Outlook, classic Outlook, Outlook on the web, Outlook for Mac, and the iOS and Android apps. Microsoft has also added a one-click summary through Copilot Chat for some users without a full Copilot license, so what you see depends on your plan and your admin's settings.

1. 1
   Select the conversation

   Open the thread in the reading pane.

2. 2
   Choose Summarize

   At the top of the email, select Summary by Copilot or Summarize, depending on your version. The summary appears above the thread.

3. 3
   Check the citations

   Summaries can include numbered citations. Select one to jump to the message it came from, which is the fastest way to verify a claim.

4. 4
   Summarize attachments separately

   In new Outlook, if the thread has a PDF, Word, or PowerPoint attachment, you can choose Summarize a file.

The manual method, for any inbox

Built-in summaries aren't on every account, and some companies turn them off. This takes about five minutes on a 30-message thread.

1. Read the first message. It tells you what the thread was originally about, which is often not what it's about now.
2. Read the last two messages. They tell you where things stand.
3. Search inside the thread for your name, and in Gmail press Ctrl+F (Cmd+F on Mac) for words like "decided", "agreed", "can you", and "by Friday".
4. Scan the middle for new attachments and for new people joining the cc line. Both usually mark a turn in the conversation.
5. Write three lines for yourself: decided, still open, asked of me.

When you're the one writing the summary

If you're catching someone up, put the summary at the top of your reply, not buried under it. Lead with the decision and the one thing you need from them. The project status update template has a structure that works for this. Once you know what's being asked, the guide on replying to emails faster covers the next step.

Comparing the ways to summarize a thread

What Synced does with a long thread

Synced reads the whole thread when a new message arrives, so the summary is a means to an end: it works out what the latest message is asking and prepares the response. You get the decision instead of the recap.

• Gmail Help: Catch up on email threads with AI Overview conversation summaries (checked 2026-09-13)
• Gmail Help: Collaborate with Gemini in Gmail (checked 2026-09-13)
• Microsoft Support: Summarize an email thread with Copilot in Outlook (checked 2026-09-13)