What is an email thread?
An email thread is a message plus all the replies and forwards that follow it, grouped together so you can read the whole back-and-forth in one place. Gmail and Outlook call this conversation view.
A thread (or conversation) is one email and every reply to it, shown as a single item in your inbox. To switch it off in Gmail: Settings › See all settings › General › Conversation view off › Save Changes. In new Outlook and Outlook on the web: Settings › Mail › Layout › Message organization. In classic Outlook: View › Show as Conversations.
See also: Using Outlook? See how to turn conversation view on or off.
What a thread is
Say Maria emails Daniel about an order. Daniel replies. Maria replies again, and adds Priya. Priya answers. That's four emails, but one conversation. An email thread keeps them together, in order, under the original subject.
You'll also hear:
- Email chain: the same thing, usually a long one.
- Conversation: Gmail's and Outlook's name for a thread.
- Threaded view or conversation view: the inbox setting that groups emails into threads. With it off, every message shows as its own line.
In Gmail, the number next to the sender's name (like "Daniel, me 4") tells you how many messages are in the thread.
How emails get grouped into a thread
Your email app decides what belongs together. Each reply carries hidden header fields that point back to the earlier message, and apps also look at the subject line.
- Gmail starts a new conversation when the subject line changes, or when a conversation passes 100 emails, according to Google's help.
- Outlook groups messages "in the same thread with the same subject line," Microsoft says.
That's why changing the subject when you reply often splits a thread in two. And it's why two unrelated emails with the same subject, like "Invoice," sometimes get grouped together.
Threaded view: pros and cons
| Threaded (conversation) view | Individual messages |
|---|---|
| The whole discussion in one place | Every message is its own line in the inbox |
| Fewer lines in your inbox | Easier to see exactly when each email arrived |
| Replies are easy to follow in order | Moving or deleting one email doesn't touch the rest |
| Deleting or archiving acts on the whole thread | Better if you file each message separately |
Most people like threads. People who file every message into folders, or who handle shared inboxes, sometimes prefer individual messages.
Turn conversation view on or off in Gmail
On a computer:
- Open Gmail and click the gear icon (Settings) at the top right.
- Click See all settings.
- On the General tab, scroll to Conversation View.
- Choose Conversation view on or Conversation view off.
- Click Save Changes at the bottom.
Gmail app on Android: tap Menu (the three lines) › Settings › your account › under General, tick or untick Conversation view.
Gmail app on iPhone or iPad: tap Menu › Settings › Inbox customizations, then turn Conversation view on or off.
The setting is separate on the computer and in each phone app. Google also notes that turning conversation view off hides "nudges," the reminders at the top of your inbox to reply or follow up.
Turn conversation view on or off in Outlook
New Outlook for Windows and Outlook on the web (Outlook.com):
- Click the gear icon (Settings).
- Go to Mail › Layout.
- Under Message organization, choose to show email grouped by conversation, or show email as individual messages.
- Click Save if asked.
Classic Outlook:
- Open any mail folder, like your Inbox.
- On the View tab, tick or untick Show as Conversations.
- Choose All mailboxes or This folder.
Classic Outlook also has View › Conversation Settings, with options like Show Messages from Other Folders (to include your own sent replies) and Always Expand Selected Conversation.
Thread etiquette
- Reply in the thread instead of starting a new email about the same topic. It keeps the history together for everyone.
- Start a new email for a new topic. Don't bury a new request at the bottom of an old thread.
- Summarize long threads before adding someone new: "Priya, quick summary: we agreed on 20 chairs, delivery June 30."
- Check the whole thread before forwarding. Older messages lower down may include things the new reader shouldn't see.
- Use Reply all carefully. Only include people who need the update. See CC and BCC explained.
Fixing common thread problems
- Can't find a reply you sent? In classic Outlook, turn on Show Messages from Other Folders so your sent replies appear in the thread. Gmail shows your replies in the thread automatically.
- Two unrelated emails grouped together? They probably share a subject line. Turn conversation view off for a moment to see them separately.
- A thread split in two? Someone changed the subject. Search for the original subject to find both parts.
- Thread too long to manage? In Gmail, a conversation over 100 emails starts a new one. Start a fresh email with a summary instead.
Questions people ask
- What is an email thread?
- An email thread is one message and all the replies and forwards that follow it, grouped together as one conversation in your inbox.
- What is threaded view?
- Threaded view, also called conversation view, is an inbox setting that groups replies with the original email instead of listing each message separately.
- How do I stop Gmail from grouping emails?
- On a computer, go to Settings, See all settings, General, choose Conversation view off, and click Save Changes. The phone apps have their own Conversation view switch in Settings.
- How do I turn off threads in Outlook?
- In new Outlook and Outlook on the web, go to Settings, Mail, Layout, Message organization. In classic Outlook, untick View, Show as Conversations.
- Why did my email thread split?
- Usually because the subject line was changed. Gmail also starts a new conversation after 100 emails.