Subject Lines That Get Opened
The most important 50 characters you'll write. Craft subject lines that stand out in crowded inboxes.
The Subject Line Problem
In the previous lesson, we explored email structure. Now let’s build on that foundation. Your email might be brilliant inside. Doesn’t matter if no one opens it.
Subject lines are the gatekeeper. In a crowded inbox, people scan subject lines and decide in milliseconds: open now, open later, or skip entirely.
Most subject lines are forgettable:
- “Quick question”
- “Following up”
- “Meeting request”
- “FYI”
- “Important”
These tell the reader nothing. They don’t stand out. They don’t communicate value.
What Makes Subject Lines Work
Effective subject lines do two things:
- Signal relevance – What is this about?
- Indicate value – Why should I care?
Both answers should be obvious from the subject line alone.
Subject Line Anatomy
Character limit: Aim for 40-50 characters. Mobile devices truncate longer subjects.
Front-load importance: First 3-4 words matter most (visible in preview).
Be specific: Vague subjects get ignored.
| Weak | Strong |
|---|---|
| Question about project | Budget approval needed – Q2 launch |
| Following up | Still need your input on vendor selection |
| Meeting | Product review – 30 min this week? |
| Important | Action needed: Contract expires Friday |
Subject Line Formulas
Formula 1: [Topic] – [Action/Status]
Best for internal communication.
- “Q2 Budget – Approval needed by Thursday”
- “Website redesign – 3 options for your review”
- “Sales meeting – Rescheduled to Friday 2pm”
Formula 2: [Result/Benefit] – [Context]
Best for external outreach.
- “15% conversion lift – Our findings from the pilot”
- “Save 10 hours/week – Automation proposal”
- “Speaking opportunity – TechConf 2026”
Formula 3: [Name/Reference] – [Purpose]
Best for networking and warm introductions.
- “Sarah Chen intro – Marketing partnership”
- “Re: Our conversation at TechConf”
- “Mike suggested I reach out – Design collaboration”
Formula 4: [Question that requires answer]
Best for getting quick responses.
- “Approve the $5K expense?”
- “Tuesday or Thursday for our call?”
- “Go with Option A or B?”
Formula 5: [Urgency indicator] – [Topic]
Use sparingly—urgency fatigue is real.
- “Decision needed today – Vendor contract”
- “Response required by 5pm – Board materials”
- “Time-sensitive: Conference discount expires”
What to Avoid
1. Vague subjects
Bad: “Question” Good: “Question about pricing on Jones proposal”
2. All caps
Bad: “URGENT: PLEASE READ” Good: “Response needed by EOD – client approval”
3. Excessive punctuation
Bad: “Great news!!!” Good: “Deal closed – Johnson account”
4. Misleading subjects
Bad: “Re: Our conversation” (when you never talked) Good: “Intro – saw your post on LinkedIn”
5. Single-word subjects
Quick check: Before moving on, can you recall the key concept we just covered? Try to explain it in your own words before continuing.
Bad: “Hi” / “Update” / “FYI” Good: “Hi from TechConf speaker” / “Project status: on track” / “FYI: Policy change effective Monday”
Subject Line Testing
If you’re unsure about a subject line, ask yourself:
- Would I open this? If you saw this in your inbox, would it stand out?
- Is it specific? Could you guess what the email is about?
- Is the key word visible? Test on mobile—can you see the important part?
- Does it promise value? Is there a reason to open?
Subject Lines by Situation
Requesting something
- “[Request] Your input on Q3 priorities”
- “Need your expertise – 5-min survey”
- “Can you review by Friday? – Contract draft”
Sharing information
- “[FYI] New expense policy – Effective March 1”
- “Meeting notes from today’s standup”
- “Report attached – Q2 results summary”
Scheduling
- “Let’s schedule: 30 min this week?”
- “Meeting request: Project kickoff”
- “Calendar invite coming – Strategy session Thurs”
Following up
- “Following up: Budget approval”
- “Checking in – Did you get my proposal?”
- “Next steps on Anderson deal”
Cold outreach
- “[Company name] + [Your company] partnership?”
- “Saw your talk at TechConf – Quick idea”
- “Intro via Sarah Chen – Possible collaboration”
Difficult conversations
- “Concern about project timeline”
- “We should discuss: Team capacity”
- “Honest feedback on the proposal”
Mobile Optimization
Over 60% of email is opened on phones. What does your subject line look like on a small screen?
Subject preview on iPhone: ~35-40 characters visible Subject preview on Android: ~30-40 characters visible
Rule: Put the most important words in the first 35 characters.
| Full subject | Mobile preview |
|---|---|
| “Following up on our conversation about the Q3 budget” | “Following up on our conver…” |
| “Q3 Budget – Your approval needed” | “Q3 Budget – Your approval nee…” ✓ |
Exercise
Rewrite these weak subject lines:
- “Quick question”
- “Following up”
- “Meeting”
- “Can we talk?”
- “FYI”
See possible improvements
- “Quick question” → “Quick Q: Tuesday or Wednesday for our call?”
- “Following up” → “Following up: Proposal status?”
- “Meeting” → “30-min sync this week? – Project update”
- “Can we talk?” → “Chat about your growth role? – 15 min”
- “FYI” → “[FYI] Office closed Friday – Holiday schedule”
Key Takeaways
- Subject lines determine if emails get opened—treat them seriously
- Aim for 40-50 characters; front-load importance
- Use formulas: [Topic] – [Action], [Benefit] – [Context], [Question]
- Be specific, not vague—give readers reason to open
- Test on mobile—first 35 characters matter most
Next: adapting your tone for different audiences and situations.
Up next: In the next lesson, we’ll dive into Tone and Voice.
Knowledge Check
Complete the quiz above first
Lesson completed!