The importance of a good email subject line

Ever since I first read Sally McGhee’s excellent book on productivity Take Back Your Life! (Microsoft Press, 2005) I have been acutely aware of the importance of writing good email subject lines.

The subject line is the message title that appears in your email client before you open the message to read it. To illustrate, here are a few emails that I received about National Youth Choirs of Great Britain-related activities:

My email client shows me who sent the email and the subject line
My email client shows me who sent the email and the subject line

Write the subject line afterwards

McGhee’s advice is to write the subject line after you’ve written your email, as the subject line should summarise what you’ve written.

How many times have you written a subject line, then written the email message, and then had to go back to edit the subject because it now doesn’t match what you actually wrote?

If the subject line is meant to be a summary of what you’ve written, then it makes sense to write it afterwards.

What makes a good email subject line?

McGhee suggests that when writing a good subject line you should make it very clear:

  1. What project or task you are communicating about.
  2. What action is being requested,
  3. Identify a due date, if there is one.

So, a subject line of “Website” isn’t really helpful at quickly conveying what is being asked. Which website? What would you like me to do with the website? Is it one that you’d like me to update, or visit, or build? Is there a deadline?


Something that I love about McGhee’s approach, that I would love to see spread more widely, is her use of action prefixes for email subject lines.

There are four different types of action, McGhee suggests:

  1. Action reqiured (AR)
    The recipient has to complete an action before they can respond.
  2. Response required (RR)
    The recipient needs only to respond. There is no action required.
  3. Read only (RO)
    The recipient needs only read the message. There is no action required, and no need to reply.
  4. For your information (FYI)
    The recipient doesn’t even need to read the message, they simply need to archive the message somewhere as it may be useful later.

McGhee then suggests prefixing the subject line with the initials of the action required. For example,

AR Project board status report required by Monday 9 January 2017

Immediately I know that I need to do something, I know what it relates to (the project board), I know what it is (a status report), and I know when it needs to be completed (Monday 9 January).

More than that, if all my emails were prefixed accordingly, I could then sort my inbox by subject line and see a prioritised list of what I need to do: act on, respond, read, or simply archive.

McGhee also has a neat practice for very short messages: write the whole message in the subject line only, so the recipient doesn’t even have to open the message, and end the message with “EOM” (end of message). For example, if I’m replying to an email trying to fix a date to meet for lunch I could write a subject line: “RO Tuesday at 12:30 is fine EOM”.

Don’t make me think!

We know from numerous studies by the Nielsen-Norman Group that screen users tend to scan rather than read every word.

Usability consultant Steve Krug encouraged digital content authors to write with a user-centred approach. His book title “don’t make me think!” has become a mantra in my team.

A bad example from my web host

I became very aware of the importance of writing good email subjects in the light of these insights these past couple of months as the renewal date for my web hosting approached.

45 days left…

On Monday 28 November I received an email from my web hosting provider telling me that I had “45 days left until service expiration”.

Fine, I thought, I have about six weeks to sort it out. I knew that I wanted to look into moving my website to another host, so pencilled in that period between Christmas and New Year to look into it; my current hosting package expires on 12 January 2017 so that would give me plenty of time.

21 days left…

On Thursday 22 December, I received another email from my web hosting provider: “21 days left until service expiration”.

I glanced at the subject line and read the opening paragraph:

There are 21 days left until the expiration of your [package] Hosting on Jan 12, 2017.

Great! I still have three weeks to do something.

14 days left… WHAT?!

So, imagine my surprise when six days later I received an email from them with the subject line “Sales Receipt”.


But my hosting doesn’t expire for another two weeks. Why are they suddenly charging me the best part of £260 now?!

That’s when I read through the rest of the email that I received on 22 December.  Paragraph two:

In order to provide you with a smooth and uninterrupted service, we will renew it automatically on the next bill date – Dec 28, 2016. We will charge you 215.46 GBP (excluding VAT) for the renewal period of 12 months.

I quickly got in touch with their support team, got a refund, and instructed them to cancel my hosting on 12 January.

What would have been a better subject line?

Looking at McGhee’s three tips for what makes a good email subject

  1. What project or task you are communicating about.
  2. What action is being requested,
  3. Identify a due date, if there is one.

we can look at the email subjects I received from my web host, and suggest how this could be improved. The email I received on 22 December read, “21 days left until service expiration”.

What project or task were they communicating about? A service was expiring. No indication which—I actually pay for two services with them. It would have been clearer if they’d indicated which one.

What action was being requested? They were implying that I needed to renew (or at least review) my hosting service.

What was the due date? Well, the subject suggested 21 days, but in actual fact I had only 7 days before something was actioned.

A better subject line would have been:

Action required: 7 days until automatic service renewal for

That is the action that I am most concerned about: when does the money get transferred out of my bank account.


I will certainly be paying closer attention to emails now, but also more careful about writing meaningful subject lines that better summarise the email message for recipients.