How to change the subject line in Gmail

A common issue in Gmail is that email threads can become long and unwieldy - sometimes bouncing from topic to topic until two parallel conversations are happening in one email, or in some cases new information surfaces that makes the original email topic irrelevant.

In both of these scenarios, changing the subject line of your email can help add clarity and direction to your email thread. 

There are two different tools that allow you to do this, and each one has a different outcome with its own benefits.

First, we’ll look at some of the scenarios in which you’d want to change a subject line, and our recommendation for each one. Then, we’ll share step-by-step instructions for each method so you can choose what’s best for your needs. 

<a href="#why-is-an-email-subject-line-important" class="anchor-link">Why is an email subject line important?</a>
<a href="#how-gmail-uses-subject-lines-to-create-a-conversation-view" class="anchor-link">How Gmail uses subject lines to create a conversation view</a>
<a href="#why-change-the-subject-line-in-gmail" class="anchor-link">Why change the subject line in Gmail?</a>
<a href="#gmails-edit-subject-line-feature" class="anchor-link">Gmail's edit subject line feature</a>
<a href="#use-streak-to-separate-emails-in-a-thread-and-change-the-subject-line" class="anchor-link">Use Streak to separate emails in a thread and change the subject line</a>
<a href="#two-methods-to-change-the-subject-line-in-gmail" class="anchor-link">Two methods to change the subject line in Gmail</a>
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Why is an email subject line important?

An email subject line is the headline of an email, the copy that first appears in the recipient's inbox. While most people often disregard their subject lines, it's actually a handy email feature that can make your email communication more effective and increase engagement.

Here's why you should make the most out of Gmail's subject line:

1. Increase open and reply rate.

Tired of sending emails that don't get replies? Maybe it's your subject line.

Recent surveys suggest that 47% of email recipients open an email based on the subject line. So, if you want people to read and respond to your email, create an interesting subject line.

2. Organize your Gmail inbox

If you're using Gmail for day-to-day email correspondence, then your subject line can be an effective organization tool.

We all know that our Gmail inboxes can become cluttered, especially if we correspond to clients and teammates daily. Fortunately, Gmail has a Label feature allowing you to tag your emails accordingly. By creating filters that look for certain words or phrases in subject lines, you can automatically label and organize your emails in your Gmail inbox. 

A clear subject line allows you to use Gmail's Labels without the need to open each email. This expedites your organization process and gives you more time to actually respond to emails instead of just looking for them in your inbox.

3. Save time for the recipients

Have you ever been too busy to read an entire email thoroughly?

Everyone has experienced that, and a clear subject line allows recipients to note the essential things without spending too much time in their inboxes.

"Meeting rescheduled to the 25th."

"New deadline for the strategy deck: Aug 9."

"Client visiting the office today."

These kinds of subject lines are life savers for busy people.
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How Gmail uses subject lines to create a conversation view

Before we explain the two different ways to change subject lines in Gmail, it’s important to understand how Gmail uses subject lines to create an email thread, or conversation view, for your emails. 

Many of us take Gmail's conversation view feature for granted, usually considering it to be the default way that our email inboxes work. But conversation view is indeed a feature, and an important one at that.

Gmail’s conversation view takes each individual email - that’s each email you send initially or as a response to somebody else - and groups them chronologically based on subject line. 

This means that when you see the subject line “Preparing for client visit” in your inbox, you can click on that one subject line and see every email that’s been sent and received in response. 

Without email threading and conversation view, each of those emails would show up in your inbox separately. It would be a mess and the conversation would be hard to follow. 

So… why does this matter? 

When you change the subject line of an email, it alters the conversation view. Creating a new subject line technically creates a new conversation, or email thread. 

The two tactics to change subject lines that we share below each take a slightly different approach and have a slightly different outcome. We'll explain how.

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Why change the subject line in Gmail?

Doesn’t it make sense to leave the subject line alone, so people know your message is continuing an established email chain? 

Well, yes. But there are some good reasons you might want to change the subject line.

1. Alert recipients to important new information

Let’s say you have an attachment everyone needs to see, or an update that changes the course of the conversation. You can change the subject line to reflect this. 

Maybe the original subject line read, “Meeting Notes for February.” You could alter it to read, “UPDATE: Schedule Attached - Meeting Notes for February” to make the thread easier to follow.

Suggestion: <a href="#editSubject">Gmail’s Edit subject line</a>

2. There was an error

Perhaps an email thread contained the subject line, “Photo Shoot Friday,” but the photo shoot wasn’t actually on Friday. Changing the subject line will help share the correct information with everybody on the thread. 

You might edit it to read, “Photo Shoot THURSDAY.”

Suggestion: <a href="#editSubject">Gmail’s Edit subject line</a>

3. There are too many tangents

It’s easy for an email thread to go off the rails. “Q4 milestones review” might quickly turn into a conversation about upcoming milestones for the next year.

To keep things organized, you may want to split the email conversation into separate threads for each topic. When you do so, you can change the subject line for the new thread to refer to upcoming milestones. 

Suggestion: <a href="#threadSplitter">Streak’s thread splitter</a>

4. Multiple teams or processes are involved

It’s not uncommon for a sales rep to be working with a lead who suddenly needs help from customer support. 

Maybe they’re locked out of their account or are experiencing a technical issue with the product. Whatever it is – the sales rep needs to loop in someone from the support team to resolve the issue and help close the deal. 

Once the support rep has been introduced, it can be helpful to split the email into two clear threads: one where the sales rep is negotiating a deal with the customer, and one where the support rep is helping the customer resolve an issue. 

When you create a new email thread for the support inquiry, you can change the subject line to be specific to the issue, like “Password reset help”.

Suggestion: <a href="#threadSplitter">Streak’s thread splitter</a>

5. The conversation needs to be searchable

Conversations with generic subject lines like “Pics” are tough to find when you need to access information in the email or refer to the thread in the future. 

To make searching for the thread easier, you might change the subject line to read “Screenshots of new feature launch from October ‘22”

Suggestion: <a href="#editSubject">Gmail’s Edit subject line</a>

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Gmail’s Edit subject line feature

Gmail allows you to change a subject line of an existing email thread when you respond in the thread. 

When you do this, you’re actually copying over the existing email thread and creating a new thread with your response and the new subject line.

You’ll end up with two threads in your inbox – one with the old subject line, and one with the new subject line.

All of the emails sent prior to editing the subject line will appear in both threads, but your response will only appear in the new one. 

To change the subject line in Gmail and create a duplicate thread:

1. Open an email or email thread in your Gmail inbox.
2. Click on Reply at the bottom of the email thread. You can also click on the Reply arrow at the top-left of the email thread.

‍

3. At the top-left corner of the reply compose window, click on the “reply” arrow with the drop-down option next to it.

4. Click Edit subject in the drop-down menu

5. This opens a compose window for your response and the subject line is highlighted. Edit the subject line as needed.

6. Click Send.
7. Optional: you may want to archive the original email thread to avoid confusion if you don’t plan to continue using that thread.

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Use Streak to separate emails in a thread and change the subject line

Streak offers another option for editing subject lines in Gmail called our thread splitter tool. It’s included in our free browser extension and allows you to select specific emails from a thread and separate them into a new email thread with a new subject line.

This is especially useful when multiple topics, teams, or processes are involved in one email thread, resulting in parallel conversations.

If you haven’t installed the free Streak extension, head over to the Chrome Web Store or the Mac App Store for Safari users to get started.

Once you have the free Streak extension installed:

1. Open the email conversation in your Gmail inbox
2. Click the three-dot “More” menu at the top of the email

3. Select “Split Thread”
4. Select the message(s) you want to separate from the conversation

5. Click “Move Messages to New Thread”
6. Enter a subject line for the new email thread and click “Done”

‍Please note that this action cannot be undone. 

Once you’ve separated the emails, you’ll find the new email thread with the subject line you entered in your inbox.

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Two methods to change the subject line in Gmail 

Editing a subject line in Gmail or using Streak’s thread splitter tool both offer free and simple ways to change the subject line of an existing conversation.

So how to you choose which one to use? 

As a rule of thumb:

• Gmail’s “edit subject line” option – keep all of the existing messages in the email thread but update the subject line moving forward. 
• Streak’s free thread splitter tool – separate some emails into a completely new thread with a new subject line.

The ability to split and rename email threads is one tool in your inbox organization arsenal. For more tips and tools, learn how you can add emails to pipelines in Gmail, track views on your sent emails, and more below.