121 Cold Email Subject Lines (Plus Data On 1M Emails Sent)

By: Jack Reamer |
 June 11, 2021 |


Did you know that 35% of people open emails based on subject lines alone? 

So, this means that if your subject line is @&$5!* then you stand a chance of losing out on 35% of prospects. But also, other studies and data have shown that subject lines don’t really have any effect on open rates

So what’s the truth behind effective cold emails?

How important are subject lines? Well, let’s have a look at data we collected after sending 1M emails and 121 cold email subject line examples

Data from 1M cold emails sent using open tracking

1. Do People open their emails based on the subject line?

Before answering this question, we need to realize that not everyone is the same. For example, in our podcast interview with Peep Laja, he mentions that he does open emails based on the subject line, whereas Jermey from Quickmail.io doesn’t. Therefore when it comes to outreach, what might make one person curious, might not for a different prospect. (Some of us just have more FOMO than others 😉 )

The data that we have collected shows that people open their emails IF it is in the prospect’s inbox. (Surprisingly, it actually doesn’t really have much to do with good subject lines). 

We also know that this isn’t an easy feat to win if you are new to cold email. Because to get into someone’s inbox means that you have to do a whole lot of things correctly from a deliverability standpoint. (And email outreach has changed a lot from a few years ago. It’s harder and harder to get into someone’s inbox.)

We had a look at the data from the best cold email subject lines and found that it had similar open rates to the worst cold email subject lines

Are we saying that a great subject line does not influence your open rate? Like, if you just had to put a dot, and some lowercase words, would people still open your email?

Well, looking at the data, a subject line does not have a major influence on whether or not you have higher open rates when prospecting

Across the board, the data shows that subject lines are not the make or break of your cold email. 

We went one step further with  A/B testing, which involved more than 1000 prospects, and we discovered that the average change between subject line variations was only a 2.5% difference in open rates

This shows that subject lines don’t really matter as much as you think they would. Your ability to inbox is far more important. Remember, your goal is to get replies, not opens. 

Instead, think of the subject line as a contract between you and your reader. Don’t use a clickbait-type subject line and then talk about something completely different in the body of the email.  

Your subject line tells the prospect what to expect, and if you violate this, they will resent you.

Here is an example:

If you’re selling surgery equipment to oral surgeons and it’s hard to build a list of surgeons who actually own a surgery unit, you could leave out the word “surgery equipment” in your subject line and have a higher email open rate.

 But you would have the wrong target audience looking at your email. 

By using the correct wording in your subject line (maybe by personalizing it a little) and letting the prospect know what’s in your email, you will call out the right people for your campaign and cut off the wrong ones.

Remember by targeting the correct email recipients, you won’t have your sales team wasting time reaching out to people who are not interested in your product. 

2. Does a low open rate lead to low reply rates?

Our data shows that, yes, low open rates do lead to low reply rates. There was a very clear coloration with this. But also, interestingly, you could have a high open rate and still have a low reply rate. 

The good news is that you stand a better chance of having a higher reply rate if you have a higher open rate.

For example, say you start off with a low open rate of below 25%. You are shooting yourself in the foot with that campaign when it comes to your chances of getting results in that campaign. This proves that deliverability is king when it comes to cold email. 

BUT with this being said, there are still a couple of guidelines that salespeople need to follow. As long as your subject line is along those guidelines, you don’t have to worry anymore about it. Your response rates are the thing to worry about. 

Have a look at our cold subject lines guidelines

  • Make sure that your sales email subject lines do not look like spam. So how would you do this? You can do this by ignoring all caps only using lowercase letters and by not putting a sales pitch in the subject line. You can also skip the emojis, as using too many looks like spam.

    The most important thing to remember not to sound spammy is: DO NOT sound salesy in the subject line. For example, “Buy now and get a free XYZ.” This sense of urgency when it comes to selling a product might land your mail up in the spam folders, which you don’t want. 

  • The next thing to remember is to have a short subject line. You could use between 1 and 3 words, with a possible question mark. By asking a question, you are opening up a person’s curiosity.
  • Make your subject line sound as if you have written the email to a colleague or a friend. This might not work in more formal countries like Germany, for example, if you are reaching out to C-level executives, but when it comes to American campaigns, we try to keep the subject line informal and casual. 
  • When it comes to cold emails, write for the reader, not for yourself. Think about what the reader would like to read.
  • Data also showed that when a company name was included in the subject line, open rates increased by 10%.  This personalized approach seemed to have worked. But strangely enough, when a prospect’s name was included in the subject line, it didn’t make a difference to the open rates.

See the graph below:

The “Quick Question” subject line analysis

We decided to use the subject line “Quick Question” and see what happened. 

Well, the data showed this subject line was across the board. 

Some people who used “quick question” as a subject line get 96% opens after sending to 250 people, and some others get 0.2% open rate sending to 331 people. This tells us that there is something else going on beyond the subject line that you choose. 

As long as you are honoring the subject line guidelines and best practices, like not sound sounding spammy and keeping your subject line short, there are bigger fish to fry besides open rate results. 


There is no quick hack when it comes to cold emailing; like you can’t just type in 3 words and expect great conversion rates, the key is to focus on deliverability and then follow subject line best practice. This will help you reach those potential customers

Be wary of blogs or marketers that offer quick hacks for subject lines that say “if you use this,” you will get higher open rates because our data of 1 Million emails have shown something quite different. 

If you’re skeptical, that’s also a good thing, then. Try testing this out for yourself and see what results you get. Try different subject lines, and see if you find any variations.

But cold email campaigns are very similar to people wanting to get a 6-pack. You can’t just swallow a pill and have your 6 pack the next morning.

It takes hard work, lots of exercises and a healthy diet. In the same way, there is no quick fix for email marketing; it takes hard work and practice.

(If you need some inspiration have a look at our cold email templates  article.)

Need more inspiration? Here are 121 subject lines to pique your interest.

Company Subject-line Email Preview in Inbox
Mixpanel Exec reach out

Hi {!first_name},

Mixpanel allows you to deeply understand every user’s journey with instant insights for everyone on mobile and …

Gusto thoughts on Gusto?

Hi {!first_name},

I know these sales emails can be a little awkward so here’s a picture of our company dog, Finnley, standing on …

ProsperWorks Google’s only recommended CRM

Hey {!first_name},

I noticed that your team is using G-Suite to support your business at {!company}. As the CRM recommended and u…

Front Front App


I hope this email finds you well. I’m John from Front — we were part of the S14 batch of YC, with the mission to build the fu…

LogDNA Re: Do you have a technical…

Hi there,

I’m the co-founder of LogDNA, my company provides server logging to engineers (something almost every companies requir…

Adroll {!first_name}, Welcome to A…

Hi {!first_name},

Let’s set up time to discuss goals for your AdRoll account and ensure you have what you need to be successful.

Datorama g’day from datorama

Hi {!first_name},

Happy Monday. I saw your company on LinkedIn and wanted to reach out. Cool to see what you guys are doing!


Swiftype Swiftype Site Search | {!co…

Hi {!first_name},

I hope this message finds you well. My name is John Doe and I manage Sales Development for Swiftype. I wanted t…

Yieldify Who/When/How?

Hi {!first_name},

Reaching out as it seems you oversee digital strategy for {!company}.

I want to introduce Yieldify’s platfor…


{!company_name} & Conversific

Hi {!first_name},

I’m John, Co-Founder of Conversific (www.conversific.com).

I wanted to personally reach you out real quick as …


401(k) with Captain401 (YC …

Hi {!first_name},

As you continue to innovate over at {!company_name} , I thought I’d drop you a quick note introducing Captain4…


Something of interest for {…

Hi {!first_name},

As a Co-founder in your industry, I wanted to reach out to you about Zenefits.

We save companies countless…

Digital Astronauts

When’s a good time?

Hey {!first_name},

We provide a level of sales infrastructure and automation that no other company can replicate. My team and I h…


{!first_name} – quick Minute

Hi {!first_name},

I hope this email find you well. I am part of a San Francisco-based, growing software development team, called …


John from Sisense Startup P…

Hi {!first_name},

I looked into {!company_name} and I’m impressed. I want to offer you a chance to join a closed startup communit…


Analytics for {!company_name}

Hi {!first_name},

Have you thought about analytics for voice and chat assistants? Dashbot is an analytics company that provides …


{!company_name} office coff…

Hope this finds you well in {!company_location}!

I wanted to ask if your team is happy with the coffee currently available there …


your product goals

Hi {!first_name},

How do you know your product team is building the right features? Are you stuck cobbling together marketing and…


{!company} employee data

Hey {!first_name},

I wanted to make sure you knew that {!company} has a public page on Comparably. Comparably for employers is so…


{!company} in Q4

Hi {!first_name},

I was reading about {!company} for a while and I’ve heard that you are looking for a smart people to join your …

Venture out NY

Time To Connect

Hey {!first_name},

I’m reaching out regarding VentureOut’s 2nd Retail Innovation Access program in partnership with XRC Labs, the…


Feedback tool for {!company…

Hi {!first_name},

I found {!company_name} on Crunchbase. It looks like a great service to {!main_function}.

I have developed a …


Hello {!first_name}, I have…

Hi {!first_name},

Are you and your team avid Slack users? Are there some integrations that you wish you had? How would you like t…

Pop Team

Hi {!first_name}!

Hi {!first_name}!

Just wanted to show you an idea for your office team.

A bit about me: I’m Jen, born in Buenos Aires, entrepr…


Available for software proj…

Hi {!first_name},

You’re hiring, and we have a community of software engineers looking for work.

I invite you to join Orbit, M…


Appropriate Person?

Hi {!first_name},

My name is John, and I saw that you work for {!company}. We help companies like yours go to market faster by f…


A new team for {!company_name}

Hi {!first_name},

Not sure if you’ve heard, but we recently started a new team focused on helping growing companies like {!compan…



Hi {!first_name}

I’m John the co-founder of StemX, I appreciate this is quite out of the blue but these days you have to think on…

Scotch & Pretzels

PR idea for {!company}

Hi {!first_name},

How is your team drumming up press for {!company}?

After spending over $100,000 in retainers, with a well k…


Insurance Help

Hey {!first_name}

My name is John and I work for a fellow tech company, Cover. We help other tech insurance companies lower their…


{!first_name} | Carta

Hi {!first_name},

Noticed you’re a co-founder over at {!company} and thought you might 


Interested in learning more?

Hi {!first_name},

Thank you for watching a quick demo of SurveyMonkey.

I’d love to get your feedback and learn about your prog…


{!first_name} – Zoom contact

Hi {!first_name},

As you have contacted Zoom, I would like to introduce myself as your new point of contact in {!country}.

I w…


Elastic Site Search – Overv…

Hi {!first_name},

We hope you found the “Elastic Site Search – Overview and Demo” video helpful. I wanted to follow up with relev…


{!first_name} – Hoping to help

Hi {!first_name}, I hope you’re doing well as Q2 is in full swing. I know you’re busy, so I’ll be brief.

Simply put – DiscoverOrg…


DocuSign Contact Us request

Hi {!first_name},

Thank you for your inquiry into DocuSign! I’m sorry I missed you, but please schedule some time on my calendar …


HubSpot | Demo Request

Hi {!first_name},

I’m reaching out regarding your interest in a demonstration of HubSpot. I will be your point of contact here at…


{{company_name}} – Zendesk

Hi {!first_name},

My name is John Doe and I am the Regional Account Executive for the SMB Mediterranean market at Zendesk.

I …


Evernote Business

Hi {{first_name}}

Thank you for contacting our team. I am more than happy to schedule a call to answer any questions you might ha…


Double your close rates wit…

Hi {{first_name}},


What’s the difference between President’s Club winners and average salespeople?


They know how t…


Are you really…you?

Hi {{first_name}},

It’s getting harder and harder to know if someone is who they claim to be online.

Identity theft is on the …


{{first_name}} – Drive grow…

Hi {{first_name}},

If you’re like most modern B2B businesses, you’re always looking for ways to leverage data in your sales and m…


{{company_name}} quick ques…

Hey {{first_name}},

Curious if {{company_name}} has to manage a bunch of separate employee systems?

We can consolidate all of …


Talkdesk meets {{company_na…

Hi {{first_name}},

My name is John from Talkdesk, a pleasure to virtually meet you.

I am reaching out because I thought it co…


Your Asana Account

Hi {{first_name}},

I’m happy to see that you’ve had such success using Asana’s free product thus far; however, most customers I w…


Let’s Meet at Dreamforce!

Hi {{first_name}} and {{second_person_first_name}},

I know your office is in San Francisco, any chance you’ll be at Dreamforce? …


Who doesn’t want to hear ab…

Hi {{first_name}},

At Paddle we’re always looking to provide insights and sharing our knowledge. We want to share with you some m…


{{company_name}} ? KickFire…

Hi {{first_name}},

{{first_colleague}} mentioned to reach out to you and I’ve called {{second_colleague}} a bunch of times and h…


PandaDoc post-{{conference_…

Hey {{first_name}},

I see that you attended the {{conference_name}} conference in {{conference_location}}. I wanted to connect an…


Capterra Reviews for {{coom…

Hi {{first_name}},

I hope all is well and you are staying safe!

As millions of software buyers are turned away from in-person …


{{company_name}} question

Hey {{first_name}},

Any openings for lunch over the next week or two (virtually, that is)?

Would love to order you lunch (wit…


Any insights from SaaStock …

Hey there {{first_name}},

SaaStock last week was pretty cool. It felt like for our company, networking was great, but booths didn…

Google Cloud

Google: Meeting Requested

Hi {{first_name}},

My name is John with Google Cloud. Now that you’ve seen all of the expert insights in our recent {{conference_…


Aircall – SaaS Growth

Hey {{first_name}},

I wanted to wait a few days before getting in touch after SaaS Growth, as I’m sure you’ve been subjected to …


Empowering you to fight cli…

Hi {{first_name}},

I’m reaching out from Stripe about a new product we’re working on to help businesses combat climate change.



Hey {{first_name}} – saw you’re using {{technology}}. Not sure if you’re aware, but we built absolutely accurate, turnkey financial …


{{first_name}}, Your 


Hi {{first_name}},

Thanks for reaching out! It’s great to see that {{company_name}} is interested in learning more about Segment….


product at {{company_name}}

Hi {{first_name}},

I’m John, co-founder at Vaporware — vaporware.net — nice to meet you.

Our super power is analyzing your …


Time to Rethink Your Outrea…

Hi {{first_name}},

Our primary goal is to help you grow your revenue. We show you how to fill your calendar with pre-qualified ap…


Quick Connect?

Hi {{first_name}},

I saw on your LinkedIn that you’re a {{title}} at {{company_name}} that I have been looking into a bit recent…


A (free) gift for team {{la…


No debating it.

They pulled through. Big time.


That rep on your team that blew out their number las…


{{company_name}} feature in…

Hi {{first_name}},

I handle partnerships for Inside.com – I came across {{company_name}} on LinkedIn today and thought I’d reach …



Hi {{first_name}},

I saw on LinkedIn you’re the Founder at {{company_name}} and thought this would be relevant to you to maximize…


Get answers to all your use…

Hi {{first_name}}!

My name is John and I’m reaching out because Mixpanel makes it easy for {{title}}s like you to understand how …


(no subject)

Hi there {{first_name}} —

John here, co-founder at Vaporware — vaporware.net.

A bit about us: we’re a team of product mana…


{{company_name}} commissions

Hi {{first_name}},

If you are like other {{title}}s leaders I talk to, tracking and verifying commissions is one of your least f…


Remember us? {{company_name

Hi {{first_name}},

It’s been a while since one of the team here last talked with you about looking to sell SaaS Subscription at a…

People Data Labs

{{company_name}}’s Data Sou…

Hi {{first_name}},

As the {{title}} at {{company_name}} it looks like you lead the charge on data sourcing and acquisition. Becau…


An idea for {{company_name}}

Hey there {{company_name}} team,

I found you on Product Hunt and think your product is fantastic. Your slogan – {{company_slogan}…


Quick Question?

Hello {{first_name}}!!

I am John DOe, currently working as a Digital Marketing Professional. Apart from that, I love blogging about…


issue for {{company_name}}?

Hey {{first_name}} — is {{company_name}} dealing with these issues right now?

1) When you hire your first employee in a new stat…


{{company_name}} / Google I…

Hi {{company_name}},

Reaching out with a Google partnerships team that sits on the ads side of the house — we’re a small team wo…


End of year strategy meeting

Hi {{first_name}},

As we approach the end of the year. I am reaching out to see if scheduling a call to discuss your end of year …


{{conference}} meeting

Hi {{first_name}},

I see you’re also attending {{conference}} tomorrow. My company (Workato) is sponsoring and I’d love to meet y…


{{company_name}}: how else …

Hi {{first_name}},

Wondering what you’re currently using to make calls, is it desk phones, mobile phones or something else?



{{first_name}} – Let’s talk…

Hey {{first_name}},

I hope you don’t mind me reaching out personally like this. We’re in the same group on {{group_name}} and I t…


Integrations at {{company_n…

Hi {{first_name}},

Out of curiosity, are any of your customers requesting integrations to systems you don’t yet support through {…


{{company_name}} & HubSpot …

Hi {{first_name}},

Hope you are having a great day! Reaching out here as I’m the HubSpot point of contact for {{company_name}}.


free to paid

Hey {{first_name}} – we just launched Retain for Trials, a new feature for Retain (our product that reduces lost customers on auto-p…


Machine-generated FB Ads – …

Hi {{first_name}}, I worked at Facebook for 7 years, and saw most of our advertisers struggle with video ad design and performance.


I can monitor Slack communi…

Hey {{first_name}},

You’re busy realising your new year’s resolutions so I’ll cut to the chase.

I’m working solo on a tool tha…


Text Analysis for {{company…

Hey {{first_name}},

I noticed that you signed up with us, and we are big {{company_name}} fans.

It looks like the team there …

Hireplicity, Inc.

Ideas For Managing Salary C…


I noticed that {{company_name}} is growing after checking your AngelList post multiple job openings. Is this the …


sales/mar-tech collab of th…

Hi {{first_name}},

As someone with a growth mindset, I figured you would be interested in the most efficient and effective way fo…

Key Take-Aways

The stats are in, and subject lines don’t make a huge difference to your open rates. The key is to get the body of your email right so that people actually want to reply to you. 

That first email is pretty essential to make a good impression. You don’t want to end up in the spam folder.

Remember to add in personalization, discuss your prospect’s pain points, and how you can be of mutual benefit.

Your email copy is important, so take some time to write something that will get your prospect’s attention

At the end of the day, you want replies because that’s what will lead to sales.

(Need some advice? Let’s set up a 15min call. Fill out the contact form below.)

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