Make sure your emails are mobile-friendly, and use a subject line tester to improve your outreach plan for the best results. The email subject line is the single most important factor in this decision-making process. It acts as the digital “front door” to your message. The challenge is real: how do you stand out without sounding like spam? Getting this right is an important skill.
Tips to Write the Email Subject Line
Here are some easy tips to ensure your emails are interesting and the users read them:
1. Use Clear and Short Subject Lines
The most effective subject lines are often the simplest. People appreciate knowing exactly what they are clicking on. In a professional setting, being clever is secondary to being clear. Studies show that subject lines with 6 to 10 words work best since they are short enough to read quickly.
Why is Length Important in Subject Lines?
Most people check their emails on mobile devices. If your subject line is too long, the most important part might get cut off by the screen. This is why you should front-load your most important keywords. If you are sending a follow-up, start with the word “Follow-up” rather than burying it at the end.
Use Action Words in Subject Lines
Use verbs that make the reader want to do something. Instead of “Meeting Notes,” consider “Look over the Monday Meeting Notes.” This gives people a reason to do something. It lets the reader know that there is a job to do within, which frequently leads to more people reading it.
2. Personalise Your Subject Line
Personalisation goes far beyond just using someone’s first name, although that is a great start. True personalisation involves making the content feel relevant to the recipient’s specific situation or needs.
- Segment Your Audience: If you are sending a mass email, don’t use a one-size-fits-all approach. Make the subject line fit the interests of the person who will get it.
- Reference Mutual Connections: When searching for an email subject line for reaching out, mentioning a shared contact or a recent event you both attended can increase open rates significantly.
- The Power of “You”: Using the word “you” makes the email feel like a one-on-one conversation rather than a broadcast.
Use Curiosity and Urgency in Subject Line
There are two main psychological triggers you can use:
- Curiosity: “The one thing you missed in the webinar…”
- Urgency: “Last chance to register for the SEO workshop.”
Both are effective, but they must be used sparingly. If every email you send is an “urgent” crisis, your audience will eventually stop believing you.
3. Use an Email Subject Line Tester
Data-driven decisions always beat guesswork. Before you hit send on an important campaign, it is wise to use a tester. These tools evaluate your text based on length, word choice, and “spammy” triggers.
How to Choose a Subject Line Tester?
A good tester will tell you if your subject line is too long or if it uses too many emojis. While emojis can add personality, they can also make your email look unprofessional or cause it to be flagged by spam filters if overused.
A/B Test Subject Lines
If you are working in digital marketing, A/B testing is your best friend. Send two different versions of your subject line to a small portion of your list. See which one gets more clicks, then send the “winner” to the rest of your audience. This method removes the ego from the writing process and relies on what actually works for your specific demographic.
| Feature | Impact on Open Rate | Recommendation |
| Personalised Name | High | Use in 1:1 outreach or warm leads. |
| Numbers/Lists | Medium | Good for newsletters and tips. |
| All Caps | Negative | Avoid; it looks like shouting/spam. |
| Sense of Urgency | High | Use only for genuine deadlines. |
| Questions | Medium | Great for sparking curiosity. |
4. Avoid Spam Words in Subject Lines
You could write the most beautiful subject line in history, but it won’t matter if it lands in the Junk folder. Email service providers are very sensitive to certain triggers.
Words to Avoid in Subject Lines
Avoid “clickbait” words like “Free,” “Cash,” “Urgent,” or “Guaranteed.” While these might seem like they would grab attention, they are the primary targets for spam filters.
Use Proper Punctuation in Emails
Limit your use of exclamation marks. One is plenty. Using three in a row (!!!) is a fast track to the spam bin. Similarly, avoid using all capital letters. It feels aggressive and untrustworthy.
Also read :
- How to Write the Best Email Newsletters—With Examples
- The Ultimate Email Marketing Guide for Beginners
- How to Optimize Your Email Campaigns
- 4 Email Marketing Jobs That Pay $20+ An Hour In 2025
- What is Email Marketing? Types, How to Do it, Examples & Benefits
- What is Email Copywriting? Examples, Tips, How to Start, and Why It’s Important
Email Subject Line Examples
To help you get started, here are several examples categorised by their purpose. You can adapt these for your own professional needs.
Subject Lines for Networking
- “Question regarding [Project Name]”
- “Fellow [University] alum looking for advice”
- “Loved your recent article on SEO trends”
Subject Lines for Follow Up
- “Following up on our chat at the PW event”
- “Checking in: [Topic] proposal”
- “Quick update regarding the internship application”
Subject Lines for Newsletters
- “5 ways to boost your website traffic today”
- “Our latest guide to mastering Google Analytics”
- “Is your SEO strategy outdated?”
Subject Lines for New Leads
- “Ideas for [Company Name]’s social media growth”
- “A quick question about your marketing goals”
- “Resources to help with [Specific Pain Point]”
How to Create an Email Subject Line Strategy?
Creating the perfect header is a skill that takes time to develop. It requires a deep understanding of your audience and a willingness to experiment. By focusing on clarity, using the right tools like a tester, and avoiding common pitfalls, you will see a marked improvement in your communication.
Remember, the goal of the subject line is not to sell the entire product or idea, it is simply to get the recipient to open the email. Once the “door” is open, your high-quality content can do the rest of the work.
Email Subject Line Checklist
Before you send your next message, run through this quick checklist:
- Is it under 50 characters?
- Did I include a relevant keyword?
- Have I checked it for “spam” words?
- Does it clearly state what is inside?
By following these four tips, you turn a simple line of text into a powerful tool for professional growth and digital engagement.
FAQs
What is the best length for a subject line?
The best length is usually between 6 and 10 words or less than 50 characters. This makes sure that mobile devices, where most people read their messages, don't cut off the text.
How can I use an email subject line tester effectively?
To check which one is the easiest to read and most interesting, you should put different versions of your header into the subject line tester.. Use the feedback to remove spam words and improve clarity.
Are emojis professional in a subject line?
In some contexts, yes. For digital marketing and casual professional outreach, a single emoji can help your email stand out. However, for formal applications or serious inquiries, it is best to stick to text.
What should I include in a subject line for reaching out to someone I don't know?
Be specific and offer value. Mention a mutual connection, a specific piece of their work you admire, or a clear reason why you are contacting them. Avoid vague headers like "Hi" or "Request."
Can you provide some examples for a job application?
Certainly. Good examples include: "Application for [Job Title] - [Your Name]" or "Referred by [Name] for [Job Title] position." These are clear and help the hiring manager categorise your email instantly.