Marketing Tools

Free Email Subject Line Generator

Generate High-Converting Email Subject Lines (Plus Preheaders)

Create catchy, click-worthy, spam-safe email subject lines tailored to your audience, goal, and offer. Get multiple variations for newsletters, promotions, cold outreach, product launches, and follow-ups—fast.

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Email Subject Lines

Your subject line ideas will appear here...

How the AI Email Subject Line Generator Works

Get results in seconds with a simple workflow.

1

Enter Your Topic or Offer

Describe what the email is about (launch, promo, newsletter, outreach). Add keywords or must-include terms to anchor the subject lines to your message.

2

Choose Type, Goal, and Tone

Pick an email type (newsletter, promotion, cold outreach), set your goal (opens, clicks, replies), and choose a tone to match your brand voice.

3

Generate, Then A/B Test

Get a list of subject lines (and optional preheaders). Select 2–4 top candidates and run A/B tests to improve open rate and downstream conversions.

See It in Action

Example of turning a generic email topic into multiple subject line options with stronger clarity, curiosity, and click-through potential.

Before

Subject: New update

We launched a new keyword research template. I want to email my list about it.

After

Subject line options:

  1. New: Keyword research template (copy/paste + walkthrough)
  2. Want my keyword research workflow template?
  3. A faster way to find low-competition keywords
  4. The template I use to plan SEO content (grab it)
  5. Keyword research, simplified: template + steps

Preheader options:

  • Includes examples + a short walkthrough.
  • Plan your next 10 posts in under an hour.
  • Copy the process, then customize for your niche.

Why Use Our AI Email Subject Line Generator?

Powered by the latest AI to deliver fast, accurate results.

High-Open-Rate Subject Line Variations

Generate multiple email subject line ideas tailored to your topic, audience, and goal—ideal for boosting open rates across newsletters, promos, and outreach.

Spam-Safe, Deliverability-Friendly Wording

Produces subject lines that avoid common spam triggers and excessive punctuation, helping improve deliverability and inbox placement.

Optional Preheader Text Suggestions

Includes matching preheader ideas to strengthen the open loop and improve click-through rate (CTR) by reinforcing the value proposition.

Goal-Based Copy Angles (Opens, Clicks, Replies)

Adapts subject line patterns to your objective—curiosity for opens, specificity for clicks, and conversational prompts for replies.

Built for A/B Testing

Creates diverse angles (benefit-led, question, social proof, urgency, how-to) so you can A/B test and quickly find what resonates.

Pro Tips for Better Results

Get the most out of the AI Email Subject Line Generator with these expert tips.

Write for one clear benefit (not five)

The best email subject lines communicate a single outcome. If your offer has multiple benefits, pick the strongest one and let the body copy explain the rest.

Pair subject + preheader to complete the message

Treat the preheader like a second line. Use it to add specificity (who it’s for, what’s included, or the next step) and increase clicks.

Use specificity to beat spam filters

Replace hype with concrete detail: “SEO checklist for new sites” usually performs better than “Amazing results inside”. Specificity helps both trust and deliverability.

Create 3 angles per campaign for fast iteration

Generate a benefit-led version, a curiosity version, and a direct version. Testing these three angles quickly reveals what your list responds to.

Avoid misleading urgency

If you use urgency, tie it to a real deadline (webinar start time, sale end date). Ethical urgency improves clicks without harming trust.

Who Is This For?

Trusted by millions of students, writers, and professionals worldwide.

Generate newsletter subject lines that increase open rates without clickbait
Create promotional email subject lines for sales, discounts, and limited-time offers (spam-safe)
Write cold outreach subject lines for B2B lead generation that get replies
Draft product launch subject lines that highlight the new feature and its benefit
Build event and webinar subject lines optimized for registrations
Refresh stale email campaigns with new angles for A/B testing
Localize subject lines for international audiences with multilingual output
Generate concise transactional email subject lines for updates, receipts, and confirmations

Write better subject lines without overthinking it

Most email campaigns don’t fail because the copy is terrible. They fail because nobody opens the email.

That’s why this page exists. Generate High-Converting Email Subject Lines (Plus Preheaders) in a couple clicks, then tweak the best options to match your brand voice. Simple.

If you’re building a repeatable workflow for emails, SEO, and content in general, you can also check out the full toolkit over on SEO Software.

What makes an email subject line convert (not just “sound good”)

A subject line has one job: earn the open. But high converting subject lines usually share a few patterns.

1) One clear promise

Pick a single outcome and make it obvious.

Bad: “Big update, lots of new things”
Better: “New keyword research template (with walkthrough)”

2) Specific beats clever

Clever is risky. Specific is dependable. Even more so for B2B lists.

Try including:

  • a number, timeframe, or result
  • who it’s for
  • what’s inside (template, checklist, invite, replay)

3) Curiosity, but honest curiosity

Curiosity works when the email actually delivers. If it smells like clickbait, people stop trusting your sender name fast.

4) A subject line is only half the story

Preheaders are basically the second sentence. Treat them like it.

Subject: “A faster way to find low competition keywords”
Preheader: “Template + step by step process I use to plan content.”

Subject line formulas you can steal (and customize)

Use these as starting points, especially if you’re stuck.

Newsletter subject lines

  • “The one thing I’d fix first in your [topic]”
  • “[Number] quick wins for [goal] this week”
  • “New: [resource] to help you [outcome]”

Promotion or sale subject lines (spam safe)

  • “[Offer] ends [day/time], here’s what you get”
  • “Last chance for [offer], closing tonight”
  • “Save on [product], built for [audience]”

Cold outreach subject lines that get replies

  • “Quick question about [specific thing]”
  • “[Company] and [outcome]”
  • “Idea for [role/team] at [company type]”

Event or webinar subject lines

  • “You’re invited: [topic] live on [date]”
  • “Reminder, we start in [time]”
  • “Replay: [benefit] in under [time]”

Follow up subject lines

  • “Still want me to send [thing]?”
  • “Following up on [topic]”
  • “Should I close the loop?”

How to use preheaders to increase opens and clicks

A good preheader doesn’t repeat the subject line. It completes it.

A few easy moves:

  • add specificity: what’s included, what happens next
  • reduce friction: “2 minute read”, “no signup”, “copy and paste”
  • add proof: “used by [type of customer]”, “tested on [context]”

If your email client shows around 40 to 90 characters, aim to make the first chunk count. Even a half sentence.

A/B testing subject lines without making it complicated

You don’t need 20 tests. You need a few clean contrasts.

Try testing 2 to 4 options across different angles:

  • Benefit led vs curiosity
  • Direct vs question
  • Short vs medium length
  • “How to” vs social proof

Then evaluate in order:

  1. open rate
  2. click rate
  3. conversions or replies

Sometimes the subject line that wins opens doesn’t win sales. That’s normal. Keep the goal in mind.

Common subject line mistakes (that quietly kill performance)

  • Too vague: “Quick update”
  • Too long: it truncates on mobile and loses the hook
  • Too many claims: reads like marketing soup
  • Fake urgency: people remember, and it trains them to ignore you
  • Spam triggers: excessive punctuation, weird capitalization, aggressive words

If you’re worried about spam language, use the “Avoid Words” field and steer the generator away from anything that feels pushy.

Quick checklist before you hit send

  • Does the subject line say what the email is actually about?
  • Is there a clear benefit or reason to open?
  • Can you make it more specific in 2 to 3 words?
  • Does the preheader add new info?
  • Do you have 2 to 4 variants ready for testing?

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Frequently Asked Questions

Yes. You can generate subject line ideas for free. Some advanced modes (like grouped A/B test sets) may be marked as premium.

Start with 10–20 options, then pick 2–4 strong candidates to test. Compare open rate first, then optimize for clicks and conversions based on your campaign goal.

It aims to avoid common spam-trigger phrasing and excessive punctuation while staying clear and persuasive. You can also add “Avoid Words” to filter out terms you don’t want.

In some audiences they can increase attention, but they can also reduce clarity or look spammy. If you rely on a professional or B2B tone, it’s usually safer to avoid emojis unless you’ve tested them.

Many campaigns perform well with short to medium subject lines (roughly 4–10 words). The best length depends on your audience, device mix, and how specific the offer is—test both short and medium options.

Yes. Select an output language to generate localized subject lines and preheaders for international email marketing.

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