How to Change the Subject When Replying in Gmail

You can change the subject of a Gmail reply on a computer from the reply’s response-type menu. This changes the outgoing message, not the subject of every earlier email already stored in the conversation or received by other people.

Open the reply you actually want to edit

Open the conversation and select the message you intend to answer. Start the reply, then check the recipients and existing text before changing its subject. If a draft is already in progress, use that draft rather than creating a second reply unnecessarily.

In a long conversation, verify the sender and date of the selected message. Changing the subject does not correct a reply that was started against the wrong message or sent to the wrong people.

Use Edit subject

1. In the reply, open the down-arrow menu beside the response type.
2. Select Edit subject.
3. Enter the subject you want for the outgoing message.
4. Review the recipients, message, and quoted content.
5. Send only when the new subject accurately describes the contents.

The composer can change its presentation when you edit the subject. Do not mistake an expanded or separate composer for a lost draft. Keep the window open until you have confirmed what it contains.

Expect conversation grouping to change

Gmail’s grouping depends on conversation characteristics, including the subject. A subject change can lead to a separate conversation rather than keeping the reply under the original thread. Other recipients’ mail clients can also present the exchange differently.

If you need an entirely new discussion with a different audience, a new message may be clearer than carrying forward a long reply history. Review what is quoted before using either approach.

Verify the outgoing result

After sending, inspect the message in Sent and confirm the subject and destination. That is different from renaming an existing inbox conversation. Do not repeatedly resend merely because the original thread still displays its old subject. If you need to clarify the topic for participants, use a deliberate follow-up rather than trying to rewrite messages already delivered.

Browse Gmail & Google Account help

References

• Reply to email
• Group emails into conversations

Reviewed against the linked official and developer guidance on October 27, 2026. Available options and screen labels can vary by account, device, region, and organization policy.