What is a Cold Email Subject Line?

A cold email subject line is the first thing you see on a cold email. It's like a summary of your email.

Why Cold Email Subject Lines are important?

There are some debates about subject lines. Some people say they are useless and that you'll get replies no matter what. I disagree, subject lines are key in cold email outreach.

They boost the open rate with the preview text

To get your emails opened, you need 2 things: a good cold email subject line and a good cold email first line.

They give the tone of your cold email

Subject lines give the tone of your sales pitch. If you're too aggressive in your subject line, you're probably also aggressive in the body.

What is a good Cold Email Subject Line?

A good cold email subject line will boost your open rate to minimum 50% even if you don't use any personalized opening lines or smart generic ones.

Think of it as a good movie title or book synopsis. It motivates you to open the email.

What is a bad Cold Email Subject Line?

A bad cold email subject line will get you low open rates, below 50% (assuming you don't have any other deliverability problems).

How to write great cold email subject lines

They're not 45 rules about writing performing cold email subject lines.

Under 5 words

5 words, 6 words, 4 words, it doesn't matter. My point is that you should keep your subject line short.

Why?

Because if you look at your own inbox, you'll notice that email marketing subject lines are super long and other cold emails you receive too.

When doing cold emailing, you need to be contrarian so do the absolute opposite.

Use of personalization

I'm not asking you to craft a unique subject line for each prospect but at least to use 1 variable like {{first_name}} or {{company}}.

We live in a world where attention is scarce so you need to hook your prospects fast.

Expert Commentary by Maria Harutyunyan, Founder of Loopex Digital

"Cold email subject lines need to be attention-grabbing and relevant. The best ones are personalized, brief, and address the recipient’s needs or interests. Avoid generic or sales phrases that can trigger spam filters. Testing different strategies—whether using curiosity, urgency, or offering value—is crucial to see what resonates best with your target audience."

Cold Email Subject Lines for Sales

When it comes to sales prospecting, I've identified 13 subject lines that are performing whatever you sell with cold emails.

Cold Email Subject Line 1: I noticed something on {{company}}

This one directly gets the attention of your recipients, they'll be like 'What is wrong with my company?".

Cold Email Subject Line 2: should we explore?

This one is more intriguing, but remember the goal of a subject line: making you read the email. Here we don't use a capital letter on purpose because it will disrupt the pattern of the recipient's inbox.

Cold Email Subject Line 3: About {{employeefirstname}}

This one takes time to prepare because you need to find the name of the recipient's employee. But they'll react this way: "What is wrong with my employee? What has he/she done?".

Cold Email Subject Line 4: Quick Question {{company}}

This sales subject line is a classic one but it's very performing.

Cold Email Subject Line 5: Solve [[problem]]

From my experience, it's not the best performing one. It all depends on how interesting is the problem you're solving.

Cold Email Subject Line 6: [[Words from a social post]]

This one is the hardest of all templates because you need to personalize every subject line for all your prospects. The reward is that you'll get exceptional open rate.

Cold Email Subject Line 7: about your company growth

This one has been performing very well for me. People are always interested in their company growth.

Cold Email Subject Line 8: about your job offer <> {{company}}

Prospects will think that you apply for their company so they will open your email. Your job will then be to come up with a sales pitch that is still linked to that subject line.

Cold Email Subject Line 9: {{company}} X [[Your Company]]

It's a classic subject line, the recipients will know that you're about to pitch something but most of them will appreciate that you go straight to the point.

Cold Email Subject Line 10: {{company}} was mentioned on LinkedIn

This subject line has been used on me and I never receive one like this before. I automatically opened the email, I was like: "where my company was mentioned?".

Cold Email Subject Line 11: {{first_name}} - quick question (10.51 s reading time)

The patter of this subject line is so special with the reading time part that it works. You also indicate the prospect that it won't take them more than 10 seconds which trick their mind.

Cold Email Subject Line 12: 11 seconds to change a {{job-name}} life

I've tried this one a few times, I noticed good results some I'm sharing it here.

Cold Email Subject Line 13: Let's break the ice {{first_name}}

Prospects will expect a personalize first line with this kind of subject line, be careful.

Cold Email Subject Lines for Networking

Here are a few subject lines for networking purposes.

Cold Email Subject Line 14: Growing a community

We grew our community, the Social Selling Mafia so easily with this subject line, it goes straight to the point.

Cold Email Subject Line 15: Want to share learnings {{first_name}}?

This one is a good way to meet new people with complementary skills of yours to build more knowledge.

Cold Email Subject Line 16: Reaching out to you via [[name]]

A classic referral networking email subject line.

Cold Email Subject Lines for SEO

When it comes to SEO, there are not hundreds of possibilities so we sticked to the working ones.

Cold Email Subject Line 17: Broken link on {{company}}

Every business owner or Head of SEO will care about broken links on their website.

Cold Email Subject Line 18: Let's share our domain authority

Assuming you have an interesting email opening line that mention your domain authority, this subject line will perform well.