Tech

How to Change Subject Line in Gmail: The Ultimate 2025 Guide on How to Edit Email Titles like a Pro

JasonAugust 4, 2025

11 7 minutes read

The subject line of an email is what your reader is first going to see. It sets tone, creates interest, and even if your email is opened or deleted. That is why it’s a useful skill to learn. Especially when responding to emails or continuing on multi-part discussions.

But hold on, here’s the thing: Gmail doesn’t make this option clear. Most people still believe you can’t alter the subject of a Gmail once a conversation has been initiated. That’s not the case.

If you’re sending a follow-up or making it the initial subject or don’t want to have your message lost in a big thread. Then altering the subject line in Gmail will make your email stand out.

Here, we are going to guide you through step-by-step instructions on how to alter the subject line in Gmail-both desktop and mobile. We’ve got expert tips, formatting tricks, and exactly when to alter the subject line to communicate better.

Table of Contents

Can You Modify the Subject Line in Gmail?

Yes. You may certainly change the subject line in Gmail, too, when you’re replying to an open string. But Gmail lacks a “Change Subject” button. You’ll need to perform a short detour via the “Reply → Edit Subject” trick.

This. It enables you to:

Start a new string of emails
Clarify or correct the initial subject line
Modify the subject of an existing conversation
Get the recipient’s attention

Altering the subject line comes in handy when:

You can reply to a long chain of emails but have to switch subjects
You do have a new request within the same chain
You need to resubmit an email for changes
You do not have to confuse people when you are having a group chat

How to Change the Subject Line in Gmail (Desktop)

Let’s see the exact steps that you have to perform in order to switch the subject line when you are replying or forwarding in Gmail.

Open the email conversation

Open the email conversation you want to reply to

Click “Reply” or “Forward”

Choose if you are replying to the initial recipient or forwarding to another recipient

Click the small arrow next to the \”Reply\” button

In the email composer, click beside the recipient’s name

Click the small arrow and choose “Edit Subject”

Gmail creates a new composition window

Congratulations, you’ve completed this step and you’re now in a new composition window, not an old-fashioned reply

You can modify the old subject line

Remove or blank out the current subject line

Enter your new subject

Enter your email message and send

This trick allows you to change the subject line without losing the email thread and without confusing Gmail’s delivery system.

Example: When Changing the Subject Line

Before: Subject: “Monthly Sales Report – March”

After: Subject: “Updated: Sales Forecasts for April – Please Review”

This slight adjustment in wording can instantly redirect the reader’s attention to the new subject line.

How to Change the Subject When Forwarding an Email

The process is slightly like replying, but easier.

Open the email
Click Forward
In the new message window, click on the subject line
Change it to your new title
Add your recipients and message, then press Send

Forwarding is all flexibility by default, no special taps required.

How to Edit Subject Line in Gmail Mobile App

The Gmail mobile app does not yet allow subject editing if you are to reply to an email conversation. But there is a workaround:

Copy and compose a new message

Open the conversation
Press the three dots and “Forward”
Select or copy the message body
Return to your inbox
Tap the + (Compose) icon
Paste the message you copied
Enter your new subject into the Subject field
Send as a new message

Take advantage of Gmail’s browser version on your phone

Open Gmail in Chrome (or Safari)
Deselect Desktop Mode through browser settings
Use desktop instructions to respond and choose “Edit Subject”
Not very user-friendly, but possible when in a hurry

Why Changing Subject Line Matters

Changing the subject line works for you:

Boost open rates on emails
Shift the direction of the reader to new priorities
Unbundle long threads for more clarity
Don’t get lost in packed inboxes
Establish next message expectations

For example, if you’re diagramming a project and need to switch from “Design Phase” to “Launch Plan,” updating the subject line replicates the notice without sending an entire new email thread.

When to Change Subject Lines (Best Practices)

Change the subject line when:

The subject of the discussion has essentially changed
You’re sending a follow-up with updated information
You want to separate different stages of a project
You’re summarizing past messages into a conclusion
You’re trying to catch attention in a long thread

Don’t change subject lines randomly. It may confuse recipients or disrupt email continuity.

Common Mistakes to Avoid When Changing Subject Lines

Don’t use misleading subject lines just to get attention
Avoid changing subjects mid-thread without context
Don’t remove the entire subject history unless it’s absolutely unavoidable
Don’t make it vague and useless words like “Hi” or “Update”

Poor subject change:

Original Subject: “Q2 Budget Planning”

New Subject: “Important” — Too general, not descriptive

Improved:

New Subject: “Q2 Budget Finalization – Require Feedback by Friday”

Can You Update the Subject of a Sent Email in Gmail?

Unfortunately not. Google doesn’t allow you to modify or change the subject line once it’s been sent.

However, you can:

Respond to your initial email using “Edit Subject”
Send the revised copy with the new subject
Send an apology or explanatory message if needed

The moment an email arrives in the recipient’s inbox, Gmail treats that email as final.

Using Subject Lines with Labels and Filters

You can apply filters on subject lines with Gmail. That is, you can automatically sort incoming emails, such as those with revised subjects.

Steps:

Click on Search bar
Enter subject:keyword
Click down arrow → Create filter
Choose such options as Apply label, Mark as read, or Skip inbox

This is handy when you change subject lines but want all the like messages all together in a single group.

Some Examples of Useful Subject Line Changes

Original: “Team Meeting – June 2”

Edited: “Rescheduled: Team Meeting – June 3”

Original: “Draft Contract Attached”

Edited: “Final Contract – Ready to Review”

Original: “Client X – Proposal Sent”

Edited: “Client X – Waiting for Response on Proposal”

These tiny tweaks clarify things and provide context to the reader immediately.

Renaming Subject Lines on Group Emails

Renaming the subject line on group emails can steer the conversation.

Tips:

Insert the change in the first sentence of the email
Save the previous context when necessary (e.g., “RE: Hiring Updates → Training Plan”)
Don’t restart the conversation completely without reason

Always monitor how the subject line looks to others, especially in cases of larger groups.

Employing Templates with Editable Subject Lines in Gmail

Gmail is now able to take advantage of Templates (once Canned Responses) as well as editable subject lines.

Setup:

Gmail Settings > Advanced > Enable Templates
Compose a message from a template
Save
When you go to repeat it, customize the subject yourself before hitting send

Templates save time, but targeted subjects make sure your email still comes through personalized.

Gmail Tips on Better Subject Lines

Keep it less than 9 words
Use action verbs (Review, Approve, Update, Schedule)
Avoid all caps (sounds too aggressive)
Personalize where possible (use name or subject)
Add dates or deadlines where possible
Use brackets for emphasis [Draft], [Update], [URGENT]

Example:

Bad: “Important!!!”

Good: “Approval Needed: Q1 Marketing Plan by Thursday”

FAQs

Can I change the subject in Gmail after clicking Reply?

Yes. Click the arrow next to Reply and choose “Edit Subject.”

How do I edit the subject on Gmail mobile?

Not particularly. You may be forced to resort to the workaround of cutting and pasting into a new message.

Will the new subject start a new thread?

Yes. Gmail treats a subject edit as starting a new conversation.

Can I keep the thread and edit the subject slightly?

Yes, but Gmail will also make a new thread by subject and content.

Will I be able to see old and new subjects by my recipient?

No. They only see the subject of the old email unless you include the old subject in the body message.

Can I input RE: or FWD: by hand?

Yes, you can input any subject format you want to type.

Does changing the subject screw up Gmail’s threading?

Absolutely, particularly if the message body changes as well.

Do edited subject lines get filtered?

If your filter has been specified to search on new subject line keywords.

Is mass-editing subject lines possible in Gmail?

No. You are not going to be able to edit more than a single subject at once.

Will editing subjects impact delivery or spam filters?

Only in the case of dubious words or misleading formatting. Always remain straight and professional.

Best Practices to Master Gmail Subject Editing

Take a moment before you respond, ask yourself if the subject still applies
Use “Edit Subject” on follow-up with new matter
Shun single-word or empty subject lines
Be professional for business communication
Use emojis only for informal or internal messages
Attachments and urgency may be added to the subject if necessary
Preview your email before it goes out
Use keyboard shortcuts to access reply/edit options more quickly

Your email’s subject line is the initial impression. It is your message header. Your capacity to edit the subject line in Gmail enables you to communicate effectively and contextually.

If you’re answering a thread that’s strayed off course, sending an alternate email, or trying to stop a thread that’s going on forever, having the option to edit subject lines in Gmail is a time-saver.

Reading all of this, you now understand how to change subject lines in Gmail on computer and phone, how to use filters and templates, and how to avoid pitfalls. You’re now ready to email smarter than ever.