The Email That Never Gets Opened
You spend 20 minutes writing the perfect email.
You check your grammar. You refine your ask. You make it professional.
You hit send.
And it sits in their inbox. Unopened. Forever.
The problem wasn't your email body. They never got that far.
The problem was your subject line.
Why Subject Lines Matter More Than You Think
Your Email Lives or Dies in 3 Seconds
Here's what happens when your email arrives:
- They see your name
- They see your subject line
- They decide: Open now / Open later / Ignore forever
That decision takes 3 seconds.
Your 20-minute email gets 3 seconds of evaluation.
If your subject line doesn't tell them why they should care, they move on.
Most Subject Lines Are Useless
These subject lines say nothing:
❌ "Quick question" ❌ "Following up" ❌ "Touching base" ❌ "Update" ❌ "Hi" ❌ "Meeting"
They can't answer:
- What is this about?
- Is it urgent?
- Do I need to read this now?
- Can someone else handle it?
Vague subject lines get ignored.
The 5 Types of Bad Subject Lines
Type 1: The Vague Non-Information
❌ "Question for you" ❌ "Need your help" ❌ "Thoughts?"
Why it fails: Could be anything. No reason to prioritize opening it.
Type 2: The Fake Urgency
❌ "URGENT!" ❌ "IMPORTANT - READ NOW" ❌ "ACTION REQUIRED!!!"
Why it fails:
- If it's actually urgent, call them
- Sounds like spam
- Boy who cried wolf—people stop believing you
Type 3: The Mysterious Hook
❌ "You'll want to see this" ❌ "This might interest you" ❌ "Opportunity for you"
Why it fails:
- Sounds like clickbait or spam
- Makes them suspicious
- Requires them to open to find out what it's about
- They won't
Type 4: The Novel
❌ "Following up on our conversation from last Tuesday about the Q4 marketing strategy and whether we should pivot"
Why it fails:
- Gets cut off after ~60 characters
- They can't see the whole thing
- Too much information = none of it registers
Type 5: The Nothing
❌ (blank subject) ❌ "Hi" ❌ "Email"
Why it fails:
- Looks like you don't care
- Could be literally anything
- Often gets marked as spam
- Shows poor email hygiene
What Makes a Good Subject Line
Principle 1: Be Specific
Tell them what it's actually about.
❌ "Quick question" ✅ "Question: Can you review slides 5-7 by Friday?"
❌ "Following up" ✅ "Following up: Budget approval for Q4 campaign"
❌ "Meeting" ✅ "Meeting request: 15 min on API migration timeline"
Why this works:
- They know what it's about instantly
- They can decide if it's relevant to them
- They can prioritize appropriately
Principle 2: Include the Action Needed
What do you need from them?
✅ "Need approval: $5K expense for conference" ✅ "Quick review needed: Client proposal (due Fri)" ✅ "Decision required: Vendor A vs B" ✅ "FYI: Server maintenance Saturday 3-5am"
Why this works:
- Clear what they need to do
- Shows if it's urgent
- Respects their time
Principle 3: Use Relevant Keywords
Put the most important words first (especially on mobile):
✅ "Johnson account - proposal ready for review" ✅ "Budget deadline - Friday EOD" ✅ "Interview: Senior Developer role - scheduling"
Why this works:
- Still makes sense if cut off
- Key information is visible
- Easy to search for later
Principle 4: Add Urgency When Appropriate
Be specific about timing:
❌ "Need this soon" ✅ "Need your input by Thursday 2pm"
❌ "Urgent" ✅ "Time-sensitive: Contract needs signature by EOD"
Why this works:
- Clear deadline
- They can plan accordingly
- Only use when actually urgent
Subject Line Formulas That Work
Formula 1: [Topic] - [Action needed]
✅ "Q4 budget - approval needed by Friday" ✅ "Client presentation - feedback requested" ✅ "Team meeting - agenda for Wednesday"
Formula 2: [Question] (quick)
✅ "Can you review PR #243 before I merge? (5 min)" ✅ "Should we use vendor A or B? (quick decision)"
Note: Only say "quick" if it's actually quick. Otherwise you're the boy who cried wolf.
Formula 3: [Action]: [Specific topic]
✅ "Approval needed: Hiring Sarah Chen as Senior Designer" ✅ "Input requested: New logo concepts (3 options)" ✅ "Decision required: Launch date (May 1 vs June 1)"
Formula 4: [FYI/Update]: [Specific information]
✅ "FYI: Client called to postpone Friday meeting" ✅ "Update: Server migration complete, no issues" ✅ "Heads up: CEO visiting office Tuesday afternoon"
Why this works:
- Clear it's informational
- Specific about what the information is
- Can deprioritize if busy
Real Examples: Before and After
Scenario: Need Budget Approval
❌ BAD SUBJECT LINES
"Quick question" "Need your help" "Budget stuff" "Can I ask you something?"
Why they fail: No information. Can't prioritize. Likely to be ignored.
✅ GOOD SUBJECT LINES
"Budget approval needed: $8K for Q4 ads (by Thursday)" "Decision: Approve Q4 marketing budget?" "Q4 marketing budget - need your sign-off by EOD Thurs"
Why they work:
- Clear what you need (approval)
- Clear what it's for ($8K, Q4 ads)
- Clear when you need it (Thursday)
- Can decide to open now or later based on priority
Scenario: Following Up
❌ BAD SUBJECT LINES
"Following up" "Circling back" "Just checking in" "Bumping this up"
Why they fail: Following up on WHAT? No context.
✅ GOOD SUBJECT LINES
"Following up: Status of Johnson proposal?" "Re: API integration timeline - still need your input" "Following up on Friday's request for design feedback"
Why they work:
- Clear what you're following up on
- Easy to connect to previous conversation
- Can search for original email
Scenario: Scheduling a Meeting
❌ BAD SUBJECT LINES
"Meeting?" "Want to talk" "Need to sync" "Got time?"
Why they fail: About what? How long? When?
✅ GOOD SUBJECT LINES
"30-min meeting request: Q4 OKRs review" "Quick call needed: Client X escalation (15 min)" "Meeting request: Discuss team restructure (1 hour)"
Why they work:
- Topic is clear
- Duration is stated
- They can evaluate if they're the right person
Special Cases
Subject Lines for Cold Emails
Rules are stricter for strangers:
❌ "Quick question for you" ❌ "Opportunity" ❌ "Can I pick your brain?"
✅ "[Mutual connection] suggested I reach out - [specific topic]" ✅ "Question about [specific thing they created/said]" ✅ "[Your role] → [Their role]: [Very specific relevant topic]"
Example: ✅ "Sarah Johnson suggested I reach out - question on API rate limiting"
Subject Lines for Group Emails
Make it clear who needs to act:
✅ "[Action needed - all]: Submit Q4 expenses by Friday" ✅ "[FYI only]: Office closed Monday for holiday" ✅ "[Leads only]: New quarterly targets"
Why this works: People know instantly if it applies to them.
What NOT to Do
❌ DON'T Use All Caps
"IMPORTANT MEETING TOMORROW"
Looks like:
- Spam
- You're yelling
- You don't know email etiquette
❌ DON'T Use Excessive Punctuation
"Question???" "Need help!!!" "Update!!!!"
Looks: Unprofessional and desperate
❌ DON'T Use Emoji (Usually)
"Question 😊" "Meeting request 📅"
Maybe OK: Very casual workplace, internal teams Not OK: Clients, formal contexts, first contact
❌ DON'T Use "Re:" If It's Not a Reply
Some people do this to make it look like an ongoing conversation.
This is deceptive and people hate it.
❌ DON'T Make Promises You Can't Keep
"This will only take 2 minutes" (it won't) "Quick question" (it's not) "No response needed" (then why are you emailing?)
Trust is hard to rebuild.
Subject Line Length
Optimal length: 40-50 characters
Why:
- Mobile devices cut off after ~30-40 characters
- Desktop shows ~60-70 characters
- Shorter = more likely to be fully visible
Test:
- Write your subject line
- Check if the key information is in the first 40 characters
- That's what mobile users will see
The 4 Tests for Subject Lines
Before sending:
1. SIGNAL: Can they tell what this is about in 3 seconds?
If you have to open the email to understand the subject line, rewrite it.
2. OPPORTUNITY: Does this tell them why they should care?
Action needed? Urgent? FYI only? Decision required?
3. RISK: Could this be mistaken for spam?
All caps, excessive punctuation, vague hooks—all look like spam.
4. AFFECT: Would you open this email?
If you'd skip it, they will too.
Subject Line Cheat Sheet
✅ DO:
- Be specific about the topic
- Include action needed
- Add deadlines when relevant
- Put key words first
- Keep it under 50 characters when possible
❌ DON'T:
- Use vague phrases ("quick question," "touching base")
- Use all caps or excessive punctuation
- Pretend it's urgent when it's not
- Leave it blank
- Write a novel
Check Your Subject Line
Not sure if your subject line will get opened?
Analyze your email free with 4Angles →
Paste your full email (including subject). See how it scores on:
- SIGNAL (Is the subject line clear?)
- OPPORTUNITY (Will they want to open this?)
- RISK (Does it look like spam?)
- AFFECT (How will they feel?)
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Related Reading
- Why Your "Quick Question" Isn't Quick
- How to Write a Follow-Up Email Without Sounding Desperate
- How to Tell If Your Email Will Get Ignored
About 4Angles: We analyze your writing from 4 psychological perspectives (Signal, Opportunity, Risk, Affect) to help you communicate with confidence. Free analysis available at 4angles.com.
Last Updated: 2025-10-28