99 Effective Cold Email Subject Lines & How to Craft Them

Created On:
January 31, 2024
Updated On:
June 24, 2024
how to craft effective cold email subject lines with templates

Cold emailing is about setting up the email infrastructure, creating lead lists, writing the email sequence, following up on the leads, closing deals, and many other steps. 

It’s easier for marketers to busy themselves with all the other steps—which are important—and forget about focusing on the subject lines.

But, when it comes to open rates, reply rates, and engagement, in general, the subject line plays the most crucial role. It’s the one and only chance to make the first impressions. 

One spammy subject line and the recipient might block you forever. This is why it’s utterly important to create the right subject line for your campaign so that you don’t diminish any chances of converting the lead. 

This article consists of 99 effective cold email subject lines that are ready for you to copy and use in your upcoming cold email campaign. In addition, there’s a detailed section on how to craft a subject line for cold emails. 

Let’s dive in.

99 Effective Cold Email Subject Lines

The 99 subject lines are divided into the following eight categories:

  1. Short subject lines
  2. Personalized subject lines
  3. Problem-solution subject lines
  4. Social proof subject lines
  5. Question subject lines
  6. Follow-up subject lines
  7. Value proposition subject lines
  8. New or update subject lines

Short Subject Lines

Short subject lines work for cold emails because they are concise, attention-grabbing, and mobile-friendly. On mobile devices, where screen space is limited, shorter subject lines are easier to read quickly, increasing the chances of recipients opening the email to learn more.

Here are ten examples of short cold email subject lines: 

  1. Quick question for you
  2. Exciting opportunity inside
  3. Important update: action required
  4. Exclusive offer for you
  5. Your expertise needed
  6. Can we talk?
  7. Special invitation inside
  8. Free consultation offer
  9. New product announcement
  10. Your input, please
  11. Don’t miss out!
  12. Exclusive offer inside

Personalized Subject Lines

Personalized subject lines in cold emails include the recipient's name or specific details about them or their company. Such subject lines grab the recipient's attention, create a sense of individualized communication, and increase the likelihood of the email being opened. Personalization shows that you've taken the time to research and tailor your message, making it more relevant and engaging.

Here are ten examples of personalized cold email subject lines:

  1. Mark, a special offer for you!
  2. Sarah, how [Recipient's Company] can benefit
  3. Personalized strategy for [Recipient's Company]
  4. Quick question for [Recipient's Name]
  5. Your impact on [Recipient's Industry]
  6. Let's discuss [Recipient's Project/Goal]
  7. A solution tailored for [Recipient's Need]
  8. Connect with [Recipient's Interest]
  9. Improving [Recipient's Pain Point] together
  10. John, I noticed [Specific Mention]

Problem-Solution Subject Lines

Problem-solution subject lines in cold emails identify a specific problem the recipient faces and offer a solution. These subject lines work wonders because they immediately address the recipient's pain points, making the email more relevant and compelling. This approach shows that you understand their needs and can provide a valuable solution, increasing the likelihood of engagement.

Here are ten examples of problem-solving cold email subject lines:

  1. Jon, quick question about [pain point]
  2. Are you struggling with [pain point]? 
  3. Struggling to Generate Leads? Let us help you!
  4. Is your website traffic plummeting? Solutions inside!
  5. Overwhelmed by data management? Simplify with our tool.
  6. Tired of late project deliveries? I can help.
  7. Experiencing high customer churn? Solution inside.
  8. Fed up with inefficient workflow? Streamline with our software.
  9. Stressed about cybersecurity threats? 
  10. Frustrated by low email open rates? I can help!
  11. Hi [Recipient's Name], a custom solution for [Recipient's Company].
  12. Your success story, [Recipient's Name]: [Your Product/Service] can help.
  13. An opportunity for [Recipient's Company] - let's discuss!
  14. Exploring [Recipient's Company]'s growth potential with [Your Solution].

Social Proof Subject Lines

Social proof subject lines showcase positive feedback, endorsements, or statistics from satisfied customers or industry experts. They benefit from cold emailing by building trust, credibility, and interest in recipients. 

Social proof signals that your product or service is valued and has a track record of delivering results, increasing the likelihood of recipients opening and engaging with your email. If you have a substantial amount of customers and boast an above average reputation in the market, leverage it in cold email subject lines. 

Here are ten examples of social proof cold email subject lines:

  1. Join 5,000+ Satisfied Customers who love our product!
  2. Trusted by Fortune 500 companies: See why they choose us.
  3. Our client success stories: Real results, real businesses.
  4. 98% customer satisfaction rating - Discover why!
  5. See how [Well-Known Company] boosted ROI by 50% with us.
  6. Industry leaders rely on our expertise – Join them today!
  7. Check out our 5-star reviews from happy clients.
  8. Over 1 million users can't be wrong - Try our solution!
  9. Recommended by [Industry Expert/Influencer] – Here's why.
  10. Trusted partner for [Number] years - Your success awaits!

Question Subject Lines

Question subject lines are designed to engage recipients by posing a question that sparks their curiosity. Open-ended questions in subject lines encourage recipients to open the email to find the answer or engage in a conversation. They create an immediate sense of involvement and interest, making cold emails more engaging and likely to be opened.

Here are ten examples of questions email subject lines for cold email outreach:

  1. What’s next, [recipient’s company name]?
  2. Want to save hours on tedious tasks?
  3. Struggling to boost your online sales?
  4. Need help finding your dream home?
  5. Curious about our latest innovation?
  6. Interested in doubling your website traffic?
  7. Wondering how to stay ahead of competitors?
  8. Looking to improve your health and wellness?
  9. Eager to enhance your customer experience?
  10. Ready to discover your perfect vacation destination?

Follow-Up Subject Lines

Follow-up subject lines are used in subsequent emails after an initial cold email to re-engage recipients. They can benefit cold email marketers by reminding recipients of previous contact, maintaining continuity in the conversation, and increasing the chances of getting a response. 

Well-crafted follow-up subject lines can capture attention and convey persistence, encouraging recipients to open and engage with your messages.

Here are ten examples of follow-up subject lines for cold email outreach:

  1. Our Next Steps
  2. Let's explore X options to get started
  3. You are not alone
  4. Can we chat for 10 minutes on [date]?
  5. A 3-step plan for your busy week
  6. Here's the information I promised you
  7. I'd appreciate your feedback on our meeting
  8. I've had some ideas since our last conversation
  9. I've been thinking about what you said
  10. What would it take to move forward?
  11. Re: [Previous Subject] - Quick Follow-Up
  12. Gentle Reminder: Let's Connect
  13. Following up on our last message
  14. Checking in: Any updates on your end?

Value Proposition Subject Lines

Value proposition subject lines communicate the unique benefits and advantages of your product or service to recipients. They highlight what sets your offering apart and why it's valuable to the recipient. Using them in cold emailing can benefit by immediately capturing the recipient's attention, addressing their needs, and increasing the likelihood of them opening and engaging with your email.

Here are ten examples of value proposition subject lines for cold email outreach:

  1. Unlock [specific benefit] with [your product/service]
  2. Experience [unique advantage] with [your solution]
  3. Maximize [desired outcome] using [your offering]
  4. Transform your [problem] into [solution] with us
  5. Achieve [result] faster and easier with [your product]
  6. Discover the power of [your product/service] for [benefit]
  7. Get [advantage] for your [specific goal] today
  8. Simplify [complex task] with [your solution]
  9. Elevate your [area of focus] with [your offering]
  10. Revolutionize [industry/process] with [your product]

News or Update Subject Lines

News or update subject lines inform recipients about relevant industry news, company developments, or product updates. Using them in cold emails benefits by grabbing recipients' attention, showcasing your knowledge, and conveying that your email contains valuable, up-to-date information, increasing the likelihood of email opens and engagement.

Here are ten examples of news or update subject lines for cold email outreach:

  • Exciting industry news: [Relevant trend or development].
  • Company X launches new product - Get a first look!
  • Important update: Changes to our service offering.
  • Breaking news in [Industry]: What you need to know.
  • [Company Name] acquires [Other Company] - What it means for you.
  • Introducing our latest feature: [Feature Name].
  • Exclusive insider insights on [Industry event or trend].
  • [Company Name] newsletter - Stay informed!
  • [Industry Event] recap: Key takeaways and highlights.
  • New research findings: [Relevant topic] report available now!

How to Craft Effective Subject Lines for Cold Email?

Crafting a subject is tricker than one imagines. However, you can always copy one that’s suitable for your campaign, create various versions of the same subject line, a/b test, and see what works best. 

This section is for people who want to write subject lines by themselves, abiding the ultimate cold email checklist.

Keep it Text-Based 

Avoid using special characters, excessive numbers, and emojis in your subject lines. These elements can trigger spam filters and make your emails appear unprofessional. Sticking to plain text ensures your emails maintain deliverability and convey professionalism. By focusing on straightforward, text-based subject lines, you increase the likelihood of your emails reaching recipients' inboxes and being viewed as legitimate, business-related communication.

Limit Length

Maintain subject lines within the range of 30 to 45 characters, which typically translates to 4 to 6 words. Short subject lines are attention-grabbing and mobile-friendly, ensuring they are easily readable on various devices, including smartphones and tablets. Concise subject lines avoid unnecessary verbosity and directly express the email's intent, compelling recipients to open them promptly.


Personalization is key to crafting engaging subject lines. Customize subject lines by incorporating the recipient's name, referencing specific details about their company, or tailoring the message to their interests. Personalization establishes a connection with the recipient, making the subject line more relevant and increasing the likelihood of them opening the email. A personalized touch creates a more meaningful and compelling first impression, ultimately leading to higher open rates and better chances of achieving the desired response.

However, manually personalizing bulk emails can be taxing. For automated personalization, use Smartlead’s spintax and custom variable tags feature.

Spintax is a text formatting technique used in content generation and email marketing. It involves using alternative word choices or phrases enclosed in curly braces and separated by vertical bars to create multiple unique variations of the same content automatically.

For example: {Hi|Hello|Hey}

In Smartlead, custom variable tags are dynamic placeholders that allow users to personalize content in cold emails. These tags can represent various data points such as dates, times, sender's name, and custom fields, enhancing the personalization and relevance of the email content.


A/B Testing

Implementing A/B testing is essential for optimizing subject lines in cold email campaigns. Continuously experiment with different subject lines to identify what resonates best with your target audience. A/B testing allows you to refine your approach based on real-time data, helping you understand which language, length, or personalization tactics are most effective. 

Utilizing tools like Smartlead, which offer A/B testing features, enhances your efficiency, ensuring that your cold email campaigns are not only personalized but also backed by data-driven insights for continual improvement.

Address Pain Points

Addressing the recipient's pain points in your subject lines is a highly effective strategy. By mentioning challenges or concerns specific to the recipient, you immediately capture their attention and convey relevance. 

For example, subject lines like “Jon, quick question about [pain point]?” demonstrate an understanding of their needs, making your email more compelling. Focusing on pain points establishes common ground, positioning your solution as a valuable resource tailored to address their specific issues.

Create Urgency

Adding a sense of urgency in your subject lines is a powerful tactic. Time-sensitive language compels recipients to open the email promptly, as they fear missing out on a valuable opportunity or limited-time offer. Subject lines like "Limited-Time: Unleash Productivity Power Now" or "Act Fast: Exclusive Software Upgrade Available" create a heightened interest, increasing the likelihood of engagement. Emphasizing urgency provides a strong reason for recipients to take immediate action, driving the desired response and enhancing the overall effectiveness of your cold email campaigns.


Subject lines play an immense role in engagement rates, especially when you’re sending cold emails. Subject sentences not only create the first impression but also directly impact bounce and spam rates. 

Alongside the above tips on how to craft a subject line, there are a few more things that one should keep in mind while deciding what subject line to use for their campaign.

You should avoid practices such as using sales-y language, employing all caps, asking for favors, using emojis, incorporating special characters, and including excessive numbers in your subject lines. These practices can affect open and reply rates, trigger spam filters, and damage trust and credibility with your audience. 

The best way to find the right subject line is A/B testing. Every customer base has different preferences. Instead of going with presumptions, it’s recommended to experiment and see what actually works. I recommend using a tool like Smartlead that will not only let you A/B test but also ensure high deliverability rates.

What’s a Rich Text element?

The rich text element allows you to create and format headings, paragraphs, blockquotes, images, and video all in one place instead of having to add and format them individually. Just double-click and easily create content.

  • dfbvrsg
  • svsv

Static and dynamic content editing

A rich text element can be used with static or dynamic content. For static content, just drop it into any page and begin editing. For dynamic content, add a rich text field to any collection and then connect a rich text element to that field in the settings panel. Voila!

How to customize formatting for each rich text

Headings, paragraphs, blockquotes, figures, images, and figure captions can all be styled after a class is added to the rich text element using the "When inside of" nested selector system.

Author’s Details

Rajnish Das

Rajnish Das is an in-house writer at SmartWriter and SmartLead. She writes product-oriented, data-driven content for B2B SaaS audiences and educates them on marketing and sales topics. Her expertise includes outbound marketing techniques like cold emailing and LinkedIn outreach.


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Frequently asked questions

General Questions

What is Smartlead's cold email outreach software?

Email automation FAQs- Smartlead

Smartlead's cold email outreach tool helps businesses scale their outreach efforts seamlessly. With unlimited mailboxes, fully automated email warmup functionality, a multi-channel infrastructure, and a user-friendly unibox, it empowers users to manage their entire revenue cycle in one place. Whether you're looking to streamline cold email campaigns with automated email warmups, personalization fields, automated mailbox rotation, easy integrations, and spintax, improve productivity, or enhance scalability with subsequences based on lead’s intentions, automated replies, and full white-label experience, our cold email tool implifies it in a single solution.

What is Smartlead, and how can it enhance my cold email campaigns?

Email automation FAQs- Smartlead

Smartlead is a robust cold emailing software designed to transform cold emails into reliable revenue streams. Trusted by over 31,000 businesses, Smartlead excels in email deliverability, lead generation, cold email automation, and sales outreach. A unified master inbox streamlines communication management, while built-in email verification reduces bounce rates.
Additionally, Smartlead offers essential tools such as CNAME, SPF Checker, DMARC Checker, Email Verifier, Blacklist Check Tool, and Email Bounce Rate Calculator for optimizing email performance. 

How does the "unlimited mailboxes" feature benefit me?

Email automation FAQs- Smartlead

Our "unlimited mailboxes" feature allows you to expand your email communications without restrictions imposed by a mailbox limit. This means you won't be constrained by artificial caps on the number of mailboxes you can connect and use. This feature makes Smartlead the best cold email software and empowers you to reach a wider audience, engage with more potential customers, and manage diverse email campaigns effectively.

How does Smartlead as a cold emailing tool can automate the cold email process?

Email automation FAQs- Smartlead

Smartlead’s robust cold email API and automation infrastructure streamline outbound communication by transforming the campaign creation and management processes. It seamlessly integrates data across software systems using APIs and webhooks, adjusts settings, and leverages AI for personalised content.

The cold emailing tool categorises lead intent, offers comprehensive email management with automated notifications, and integrates smoothly with CRMs like Zapier, Make, N8N, HubSpot, Salesforce, and Pipedrive. Smartlead supports scalable outreach by rapidly adding mailboxes and drip-feeding leads into active campaigns Sign Up Now!

What do you mean by "unibox to handle your entire revenue cycle"?

Email automation FAQs- Smartlead

The "unibox" is one of the unique features of Smartlead cold email outreach tool, and it's a game-changer when it comes to managing your revenue cycle. The master inbox or the unibox consolidates all your outreach channels, responses, sales follow-ups, and conversions into one centralized, user-friendly mailbox.

With the "unibox," you gain the ability to:
1. Focus on closing deals: You can now say goodbye to the hassle of logging into multiple mailboxes to search for replies. The "unibox" streamlines your sales communication, allowing you to focus on what matters most—closing deals.

2. Centralized lead management: All your leads are managed from one central location, simplifying lead tracking and response management. This ensures you take advantage of every opportunity and efficiently engage with your prospects.

3. Maintain context: The "unibox" provides a 360-degree view of all your customer messages, allowing you to maintain context and deliver more personalized and effective responses.

How does Smartlead ensure my emails don't land in the spam folder?

Email automation FAQs- Smartlead

Smartlead, the best cold email marketing tool, ensures your emails reach the intended recipients' primary inbox rather than the spam folder. 

Here's how it works:
1. Our "unlimited warmups" feature is designed to build and maintain a healthy sending reputation for your cold email outreach. Instead of sending a large volume of emails all at once, which can trigger spam filters, we gradually ramp up your sending volume. This gradual approach, combined with positive email interactions, helps boost your email deliverability rates.

2. We deploy high-deliverability IP servers specific to each campaign. 

3. The ‘Warmup’ feature replicates humanized email sending patterns, spintax, and smart replies.
4. By establishing a positive sender reputation and gradually increasing the number of sent emails, Smartlead minimizes the risk of your emails being flagged as spam. This way, you can be confident that your messages will consistently land in the primary inbox, increasing the likelihood of engagement and successful communication with your recipients.

Can Smartlead help improve my email deliverability rates?

Email automation FAQs- Smartlead

Yes, our cold emailing software is designed to significantly improve your email deliverability rates. It enhances email deliverability through AI-powered email warmups across providers, unique IP rotating for each campaign, and dynamic ESP matching.
Real-time AI learning refines strategies based on performance, optimizing deliverability without manual adjustments. Smartlead's advanced features and strategies are designed to improve email deliverability rates, making it a robust choice for enhancing cold email campaign success.

What features does Smartlead offer for cold email personalisation?

Email automation FAQs- Smartlead

Smartlead enhances cold email personalisation through advanced AI-driven capabilities and strategic integrations. Partnered with Clay, The cold remaining software facilitates efficient lead list building, enrichment from over 50 data providers, and real-time scraping for precise targeting. Hyper-personalised cold emails crafted in Clay seamlessly integrate with Smartlead campaigns.

Moreover, Smartlead employs humanised, natural email interactions and smart replies to boost engagement and response rates. Additionally, the SmartAI Bot creates persona-specific, high-converting sales copy. Also you can create persona-specific, high-converting sales copy using SmartAI Bot. You can train the AI bot to achieve 100% categorisation accuracy, optimising engagement and conversion rates.

Can I integrate Smartlead with other tools I'm using?

Email automation FAQs- Smartlead

Certainly, Smartlead cold email tool is designed for seamless integration with a wide range of tools and platforms. Smartlead offers integration with HubSpot, Salesforce, Pipedrive, Clay, Listkit, and more. You can leverage webhooks and APIs to integrate the tools you use. Try Now!

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Is Smartlead suitable for both small businesses and large enterprises?

Smartlead accommodates both small businesses and large enterprises with flexible pricing and comprehensive features. The Basic Plan at $39/month suits small businesses and solopreneurs, offering 2000 active leads and 6000 monthly emails, alongside essential tools like unlimited email warm-up and detailed analytics.

Marketers and growing businesses benefit from the Pro Plan ($94/month), with 30000 active leads and 150000 monthly emails, plus a custom CRM and active support. Lead generation agencies and large enterprises can opt for the Custom Plan ($174/month), providing up to 12 million active lead credits and 60 million emails, with advanced CRM integration and customisation options.

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What type of businesses sees the most success with Smartlead?

No, there are no limitations on the number of channels you can utilize with Smartlead. Our cold email tool offers a multi-channel infrastructure designed to be limitless, allowing you to reach potential customers through multiple avenues without constraints.

This flexibility empowers you to diversify your cold email outreach efforts, connect with your audience through various communication channels, and increase your chances of conversion. Whether email, social media, SMS, or other communication methods, Smartlead's multi-channel capabilities ensure you can choose the channels that best align with your outreach strategy and business goals. This way, you can engage with your prospects effectively and maximize the impact of your email outreach.

Email automation FAQs- Smartlead

How can Smartlead integrate with my existing CRM and other tools?

Smartlead is the cold emailing tool that facilitates seamless integration with existing CRM systems and other tools through robust webhook and API infrastructure. This setup ensures real-time data synchronisation and automated processes without manual intervention. Integration platforms like Zapier, Make, and N8N enable effortless data exchange between Smartlead and various applications, supporting tasks such as lead information syncing and campaign status updates. Additionally, it offers native integrations with major CRM platforms like HubSpot, Salesforce, and Pipedrive, enhancing overall lead management capabilities and workflow efficiency. Try Now!

Email automation FAQs- Smartlead

Do you provide me with lead sources?

No. Smartlead distinguishes itself from other cold email outreach software by focusing on limitless scalability and seamless integration. While many similar tools restrict your outreach capabilities, Smartlead offers a different approach.

Here's what makes us uniquely the best cold email software:

1. Unlimited Mailboxes: In contrast to platforms that limit mailbox usage, Smartlead provides unlimited mailboxes. This means you can expand your outreach without any arbitrary constraints.

2. Unique IP Servers: Smartlead offers unique IP servers for every campaign it sends out. 

3. Sender Reputation Protection: Smartlead protects your sender reputation by auto-moving emails from spam folders to the primary inbox. This tool uses unique identifiers to cloak all warmup emails from being recognized by automation parsers. 

4. Automated Warmup: Smartlead’s warmup functionality enhances your sender reputation and improves email deliverability by maintaining humanised email sending patterns and ramping up the sending volume. 

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How secure is my data with Smartlead?

Ensuring the security of your data is Smartlead's utmost priority. We implement robust encryption methods and stringent security measures to guarantee the continuous protection of your information. Your data's safety is paramount to us, and we are always dedicated to upholding the highest standards of security.

How can I get started with Smartlead?

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Getting started with Smartlead is straightforward! Just head over to our sign-up page and follow our easy step-by-step guide. If you ever have any questions or need assistance, our round-the-clock support team is ready to help, standing by to provide you with any assistance you may require. Sign Up Now!

How can I reach the Smartlead team?

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We're here to assist you! You can easily get in touch with our dedicated support team on chat. We strive to provide a response within 24 hours to address any inquiries or concerns you may have. You can also reach out to us at support@smartlead.ai

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