How Brackets Improve Email Subject Lines

We all complain about receiving too many emails, but perhaps what we really need to do is to make faster decisions about the emails we receive. That starts by using clearer subject lines.

One of the simplest ways to improve the emails you send is to add a bracketed phrase at the beginning of your subject line. A bracketed subject line acts like a road sign; it gives people an instant sense of what to expect. 

Examples look like this:

• [FYI] Notes from yesterday’s client call attached

  
  

• [Action Required] Complete compliance training by Friday 

  
  

• [For Review] Slide deck for next week’s town hall

These short cues help your recipients quickly understand what kind of message it is and what (if anything) they need to do. They require minimal effort but reap big rewards.

Let’s look at why this works.

Brackets Help People Triage Their Inbox Faster

The average office worker receives dozens of emails each day. When subject lines lack context, recipients have to spend extra time opening and scanning to figure out:

• Is this urgent?

  
  

• Is this for me?

  
  

• Do I need to reply?

  
  

A simple bracketed cue up front removes that guesswork. It gives people the context they need to act faster or to decide if it can wait.

Time savings can add up quickly. Imagine a department of 30 people, each receiving 75 emails a day. That’s 2,250 emails across the team—every day.

If it takes 4 seconds on average to triage an email message without a clear subject line and 2 seconds with bracketed subject lines, you’re saving:

• 2 seconds per email

  
  

• 150 seconds (2.5 minutes) per person, per day

  
  

• Over 10 hours per person, per year

Multiply that across the team and you’ve saved more than 300 hours annually. That’s the equivalent of nearly 8 full workweeks reclaimed, just by making the subject lines easier to scan. 

And that’s just the time saved in first-glance triage. Add in fewer follow-ups, missed deadlines, and clarifying pings, and the efficiency gain grows even more. A few words in brackets can have a compound effect on clarity and time.

Brackets Can Become a Shared Language

Adding bracketed cues to the start of subject lines works best when a team—or even everyone in the organization—uses brackets consistently. Think of brackets as a kind of internal shorthand, like subject line hashtags that align your communication.

Here are six bracketed tags I use regularly, with notes on when they’re most helpful:

• [FYI] – Use when no response is needed.

  
  

• [Action Required] – Use when the recipient must take a specific step.

  
  

• [Request] – Use when you’re asking for something, but it’s not urgent.

  
  

• [For Review] – Use when you want feedback on a document or idea.

  
  

• [Reminder] – Use to follow up on something you’ve already mentioned.

  
  

• [URGENT] – Use only when it’s truly urgent—and if it is, maybe pick up the phone instead.

  
  

Once these brackets become part of your team’s habits, communication speeds up and misunderstandings go down. You can even standardize the practice by agreeing on 5–7 go-to tags and modeling their use in your own emails.

After you’ve become comfortable with a few core bracketed tags, you might start using others that fit your role or recurring communication needs. Here are some examples to get you thinking:

[Update] [Feedback Needed] [Deadline: MM/DD] [Confidential] [Important] [Results]

[Meeting] [Announcement] [Webinar Reminder] [Registration Closing Soon] [Invitation]

[Confirmation] [Invoice] [Introduction] [Minutes]

---

You don’t need a department-wide policy to get started. Just try adding one bracketed cue to your next subject line. See how people respond. Notice if you get replies faster or fewer clarifying questions.

If it works, share it with your team so everyone can benefit.