Writing email subject lines is one of the toughest parts of email marketing. That’s because after all the work invested in the body text and design, you need to convince your target to open the email.
And you have less than 70 characters to do so, which leaves little room for error. Forty percent of consumers have 50+ unread emails in their inbox, according to Hubspot, and you don’t want to enter that tally.
In this guide, you’ll learn how to write good email marketing subject lines and the mistakes to avoid. We also include examples, such as the best subject lines for nurturing cadences and sales emails, so you hit the proverbial nail on its head with your audience.
In this article
What makes a good email subject line?
Is there a magic formula for successful email marketing subject lines? Honestly, no. But there are guidelines to boost the click-through rate (CTR) and avoid emails staying unread:
- 70 characters or less: With the rise of mobile readership, “short and sweet” is more desired than ever. People check emails on their phones during the commute, which means less real estate for subject lines. Restrict the character count to avoid copy being cut off.
- Personalization and the 2nd person (you): We resonate with our names in a text. And the same goes with “you” because it’s conversational and addresses us directly. So, set up personalization tags and write in the 2nd person.
- Write multiple subject lines and A/B test: To prove the best subject line, test its engagement. Use Customer Relationship Management (CRM) or Marketing Automation Platform (MAP) to set up A/B tests for your emails and pick the one with the highest CTR.
- Include a call-to-action (CTA): Muster a response from the reader with a verb, takeaway, or intriguing fact in the subject line. Avoid spammy, overused phrases such as “buy now” and remember—emails that don’t inspire action are usually ignored.
- Know your audience: As is true in all communication, you won’t drive impact if you don’t know the lingo and worldview of your audience. Buyer personas, demographics, psychographics, and surveys help you address your public in subject lines.
- Preview your emails: To make sure your subject line and the body text are what you expect, preview them before sending en masse. It’s also a good idea to send yourself a test email and view it on desktop and mobile.
Best subject lines for email marketing
For email marketing, the goal is to drive action for a campaign. So, the best subject lines for email marketing entice the reader to perform a certain action after opening the email.
For example, imagine you are a Spanish teacher and you have a list of 100 leads that downloaded a “Spanish Basics” eBook. Your goal now is to enroll them in your Beginners course, so you send the following email:
[Name], enroll in the Spanish Beginners course
This subject line is fine, but not exceptional. That’s because it doesn’t provide any value to be gained from enrolling in the course. However, the following copy does:
Exclusive Spanish course discount for eBook readers
Now this subject line provides value (an exclusive discount). But how to improve even further? Personalize the copy:
[Name], a gift for reading my eBook: Spanish course discount
You’ve got a convincing subject line now. And you should apply this framework for all email marketing: how to convince my reader to open—and perform the action I want?
This applies to signing up for a webinar, watching a video, clicking on a blog post, viewing a product demo… it’s the same structure with slight variations according to your niche. A/B tests and experience will teach you the variations for your industry that work best.
Email marketing subject line examples
Keep this list handy for your next marketing email blast:
- [Topic] takeaways: 5 takeaways from SEO experts for blogging in 2021
- How to: How to not procrastinate at work [Guide]
- You vs. them: Your performance compared to the Fortune 500
- Results: Reveal Mobile achieves 200% ROI with precision targeting [case study]
- Avoid/Prevent X: Avoid these 5 common SDR mistakes
- Three items: Rio, L.A., and London: Your next vacation awaits
- Usage of pipes ( | ): PlayStation Indies | Enjoy unique and innovative experiences
- Here’s why: Here’s why you should consider TikTok marketing
Best sales email subject lines
There are two ways to write good sales email subject lines: Strike a conversation or go straight for the pitch.
If your audience prefers humane communication, then the first option is your choice. Whereas if your prospect is “straight to the chase” then make the value of your offer clear when they open their inbox.
And as mentioned in the previous “what makes a good email subject line?” item, A/B testing is your friend to discover the highest-converting lines for sales emails.
Anyway, let’s go over examples for conversational and pitch-focused sales email subject lines below:
Conversational subject line examples
- Hoping to help X: [Name], hoping to help with your product launch
- [Benefit] for you: [Name], I have 10 qualified leads for you
- Ideas for X: I have 3 ideas for your next meeting
- Question about X: [Name], question about your management style
- [Referral]: [Name], [referral] mentioned you need help
Pitch-focused subject line examples
- 15 minutes for X: [Name], 15 minutes to discuss account based marketing?
- Meeting invite [date]: Meeting invite on Mon Sep 27
- Permission to close?: [Name], permission to close the deal?
- Next steps: [Name], view our next steps together
- Here’s my pitch: [Name], here’s my pitch on the benefits of bunk beds
Best subject lines for email cadences
Email cadences (also known as drip campaigns) are a series of automated emails designed to nurture a lead.
In case you aren’t familiar with the term, lead nurturing means to develop a relationship with the prospect and foment interest in your products until they are ready to buy. And depending on your niche, cadences can be short (such as a fashion brand) or long, as is the case for most B2B enterprises.
Below we present subject lines for each moment of this email cadence, known as a touch, in which you’ll nurture the lead with content:
First touch email subject line examples
Conversational-style subject lines are a great fit for this step since they set a friendly tone for the start of the cadence.
For the first email, you’ll need to greet the prospect. This can be done with a welcome email, an onboarding, or even a personal introduction.
- Welcome [name]: Welcome [name] to [brand]
- Hi [name]: Hi [name], let me introduce myself
- [Name], glad to have you: [Name], glad to have you onboard
- [Name], get started: [Name], get started with [brand]
Second touch email subject line examples
For the second email, you need to promote content that engages the lead. This could be insights from a blog post, an interesting statistic, or even a whitepaper.
In many cases, the introductory email is ignored, so this is your second chance to get the email opened.
- [Name], [Data]: [Name], the US is the largest market for Mobile Ads
- [Name], X insights from Y: [Name], 3 insights from our Mobile Ads report
- [Name], letter from X: [Name], letter from our CEO on Mobile Ads
- [Name], view our trending X: [Name], view our trending Mobile Ad posts
- [Feature] to help your business: 500 on-demand experts to help your business
Third touch email subject line examples
For the third email, you need to warm up the lead for a pitch. This can be with a high-value asset, such as an eBook, or a list of benefits of your services.
The focus now is to promote value (not a sale), so don’t overstep and let the pitch happen in the final email.
- X benefits: 5 benefits of Mobile Ads for small businesses
- [Name], [asset]: [Name], Mobile Ads eBook for small businesses
- Case study: Mobile Ads [client name] case study
- Why X: Why Mobile Ads increase sales for small businesses
- Important things to know: 3 important things to know about Mobile Ads
Fourth touch email subject line examples
Finally, the time has come for the pitch email. Now you can present a unique offer and include CTAs to book a meeting with an SDR.
Keep in mind that you should send this pitch only to leads that opened the former emails and clicked on internal links. You won’t make a sale to a lead that ignored your campaign entirely.
Instead, place leads that ignored emails on a different email cadence, focused on the top of the sales funnel (awareness stage) and promotion of informational content.
- CEO offer: [Name], our CEO offers a personalized ads program for you
- Best solutions for you: [Name], best Mobile Ad programs for [lead’s company]
- X reasons why : 3 reasons why will increase your ROI
- X% off: [Name], 10% off
- Meeting to discuss X this [date]: [Name], meeting to discuss Mobile Ads this Tuesday?
Funny email subject lines
Humor works if you know your audience. Otherwise, it’ll miss the target and can even be considered unprofessional. So, tread carefully with humor but don’t be afraid to tickle a funny bone, and most importantly—get that email opened.
If you’re reluctant to fire away emails with jokes, then test the approach on social media first. If the public resonates (and it doesn’t flop), then you’re safe to jest in emails too.
Funny email subject line examples
- Song lyrics: [Name], never gonna give you up
- Dad jokes: I ordered a chicken and an egg online. I’ll let you know.
- Trending topics: Looking like Kim at the Met Gala…
- Puns: Witch, please (Halloween themed email by ModCloth)
Email subject lines to avoid (spam triggers)
Spam filters have evolved in past years to contextually identify spam rather than focus on keywords alone, but it’s best to avoid the following in your campaigns:
Keywords commonly used by scammers, so avoid them if possible. Unfortunately, even if your email is legit, it might be targeted by filters. The following is merely a short list:
- Social security number
- US dollars
- Luxury car
“Too good to be true” phrases
Unbelievable promises are detected by filters as well. So don’t use these phrases in your subject lines:
- Double your income
- Earn cash
- Eliminate debt
- Increase sales
- Money back
- Free investment
- Fantastic deal
- Lose weight
- Stop snoring
- No fees
- No questions asked
If it reads like an 80s TV ad, then your email might go to spam. Avoid anything BUY NOW-style, like the phrases below:
- Apply now
- Act now
- Call now
- Get started now
- Click here
- Do it today
- Take action
- Limited time
- Once in a lifetime
- While stocks last
- Special promotion
Email subject line generators
Whenever you’ve got writer’s block and need a high-converting subject line ASAP, generators are a handy tool.
Keep in mind these tools usually throw your keyword into a template, so editing is needed. Even so, a subject line generator provides good ideas and a place to start when you feel stumped.
Here are four tools to create email subject lines:
With this generator, simply pick a category for your keyword (Benefit, Topic, or Pain Point) and you’ll receive four suggestions.
As a test, we got the following suggestions for the keyword “decrease churn” in the Benefit category:
- The secret to decrease churn
- The ultimate guide to decrease churn
- What you should know about decrease churn
- A toast to decrease churn
We like the last one best (very intriguing).
This tool is similar to the previous one: Pick a category (Benefit, Problem, Personalized, Covid-19) and type your keyword.
We’ll use the same example (decrease churn) and the Benefit category to test this tool out. Here are the results:
- How to take the headache out of decrease churn
- For when you need decrease churn
- The lazy person’s way to decrease churn
- The fastest way to decrease churn
- Answered: your most burning questions about decrease churn
- A little known way to decrease churn
Like last time, we believe the final cold email churned out by Reply.io is the best.
This tool is different from the others as it is a title generator rather than a subject line creator. Even so, it is a valuable asset for quick inspiration.
Simply type in your keyword (yes, we used “decrease churn” again) and click on “Generate idea”. Here are the results of our test:
- Why decrease churns are cuter than a kitten
- 18 things Spock would say about decrease churn
- 9 ways decrease churn can increase your productivity
- How decrease churns are the new hotness
As you can see, some ideas are nonsensical. But even from the absurd emerges reason (or at the very least engaging subject lines). We would love to know 18 things Spock has to say about decreasing churn.
Rather than a generator, this is a list of over 100 subject lines with blanks to fill in with keywords. The list never changes, so if you’d rather paste the list onto a doc (or even print it out), you can.
Here are what the first five examples provide with “decrease churn” as a keyword:
- Decrease churn changed my life forever.
- The first time I heard about decrease churn it changed everything.
- I never knew the impact decrease churn would have on me.
- The best thing about decrease churn was the way it changed my life.
- When I got good at decrease churn it changed my life.
You’ll probably trim down most examples for it to work in email marketing, but some handy inspiration nevertheless. We like the third one best.
After going through many email subject examples, from the salesy to the funny, here are four takeaways to remember next time you’re writing copy:
Simple is better
Focus on communicating one thing with your subject lines. Your goal is to get the prospect to open the email, so make sure there’s a clear reason to do so.
For example, in the subject line “I have 3 ideas for your next meeting”, the reader knows they’ll discover 3 ideas. That’s the value and why they should open the email.
Get to know your readers and do A/B tests
More than any marketing best-practice can preach, what works most with email is knowing your audience. That means knowing the words that drive the CTR up that only experience will reveal—experience fueled with insights from A/B tests.
So, write multiple subject lines and test them with your public. Keep notes on what words perform best, as well as product features, and tone (salesly, funny, approachable, etc).
Check your emails before hitting “send”
Many blunders have been committed by brands for not checking before sending an email blast to clients. Preview the email and send yourself a test before launching your email marketing campaign.
Also, spell check to avoid embarrassing typos that can diminish your credibility.
Remove any potential spam triggers
Apart from the grammar check we mentioned before, see if your email has any words that can be picked up by spam filters.
Just remember to consult this article and eventually you’ll internalize what words you can’t use. Keeping the spammy words on a spreadsheet or even a printout also helps.