How to write subject lines for internal emails that actually work

Swipe right on better open rates: how to write subject lines for internal emails that actually work

Subject lines are the Tinder bios of internal emails. You’ve got one line to spark curiosity, show a little personality and maybe (just maybe) earn a click. No pressure.

But if you’re sending emails to a busy workforce of people juggling meetings, assignments and Slack messages (and probably 37 open tabs), then you know how easy it is for your message to get lost in the noise. And while most internal comms folks aren’t moonlighting as dating app profile writers, the challenge is basically the same: how do you stand out in a crowded inbox full of boring or immediately forgettable messages?

Employees don’t ignore internal emails because they don’t care. They ignore them because there’s too much coming at them, and subject lines like “New policy update” or “June monthly digest” just don’t cut it. That first line of text — in other words, what they see in their inbox preview — is your only shot at convincing someone your email is worth their time.

But here’s the good news: you don’t need to be a professional writer to craft a good subject line. You just need the right data, a few best practices and a tool like Workshop, that’s built for internal comms (and not just marketing blasts).

We analyzed over 100 million internal emails to figure out what really works when it comes to subject line best practices, from length and tone to personalization and testing. And now, we’re pulling back the curtain on what high-performing internal subject lines have in common, where things tend to go wrong and how you can write better internal emails starting today.

The tea on emails: what researching millions of subject lines told us

When it comes to internal communications, the subject line isn’t just a formality. It’s a deciding factor. And thanks to our 2025 Internal Communication Benchmarks & Best Practices Report, we’ve got the receipts to prove it. In reviewing internal emails across industries, teams and even different use cases, we developed a massive data set that gave us a crystal-clear view of what works (and what doesn’t). And when it comes to writing subject lines that actually get opened, here’s what we found:

1. Personalization works (big time)
Emails with personalized subject lines consistently outperformed the rest. Including a recipient’s first name can improve internal email open rates by as much as 17%. Why? Because people are more likely to engage when something feels tailored to them. (Check out the info on merge tags below!)

2. Emojis aren’t dead ⚰️
Strategically placed emojis still have a role. Especially in more casual communications like culture updates, event invites or shoutouts. But moderation is key. One emoji? Great. Two or three? Suddenly, your email looks like spam. So use them sparingly and intentionally.

3. Corporate jargon can tank performance
The best-performing subject lines are simple, specific and human. That means skipping the buzzwords (no one’s clicking on “Strategic alignment updates”) and cliche jargon. Your employees aren’t robots, so your subject lines shouldn’t be either.

If your open rates aren’t where you want them to be, subject line optimization is one of the fastest, easiest levers you can pull. And with the right tools, you can make it part of your everyday process (no guesswork required). So, what’s the recipe for a subject line employees will actually click? From personalization to emoji use to clarity over cleverness; next up, we’ll dive into see what separates the subject lines that get opened from the ones that get ignored.

Anatomy of a great subject line

You might assume employees open every work email simply because they’re expected to. But let’s be real: no one reads every single email they get. If you want to gain the coveted click, you need a great subject line. They are a critical predictor of open rates in internal emails, especially when it comes to clarity and length.

And our data confirms it: short, clear subject lines consistently outperform the long-winded or overly clever ones. The sweet spot? 21-40 characters. Go much longer, and open rates drop fast. What else makes a great subject line? Well, in our research, we found that the best subject lines for internal communications are typically:

• Clear: “Benefits enrollment ends Friday” beats “Important HR update” every time.
• Short: Just enough to be informative, not so long that they get cut off.
• Aligned: The subject line accurately reflects what’s inside (no clickbait allowed).
• Urgent or create curiosity: If your message is time-sensitive or interesting, lead with it.

The goal isn’t to be witty. It’s to be unmissable. If you want a quick gut check, ask yourself: Would I open this if it landed in my inbox? If the answer is no, it’s worth another draft. And if you need help pressure-testing your ideas, Workshop’s pre-send previews let you see how your subject lines look across devices, inboxes and character limits, so you can hit send with confidence.

(PS: Want some quick subject line examples? Grab our free inspiration library, which comes with a handy checklist to help you craft with confidence.)

Personalization with merge tags

If you really want your subject lines to stand out, personalization is your secret weapon. We’re not talking about creepy, overly familiar messages that feel like a marketing ploy. We’re talking about smart, subtle personalization that signals relevance, like including the recipient’s name, department, location or even their role. When done well, it can make your emails feel more like a direct message and less like a corporate broadcast. And it can increase your engagement.

Workshop makes this kind of personalization super simple with merge tags. You can drop dynamic fields directly into your subject line, like:

• Hey [First Name], your training starts soon
• Reminder for [Department]: Submit your Q3 goals
• [Location] crew: Friday’s lunch is on us 🥪

Here’s where it gets even more powerful. Workshop integrates with your HRIS (Human Resources Information System), so you can pull in any employee data field you might already be tracking. So, anything from first name to exemption status, t-shirt size, work anniversary or even preferred pronouns can work. Bottom line: If it lives in your HRIS, you can use it to personalize your employee emails.

These little touches can make a big impact, especially when employees are scanning their inbox at lightning speed. It helps them instantly recognize the email’s relevance. And unlike trying to hack something together in Outlook or another generic email marketing platform, Workshop was built for this kind of thing. Merge tags integrate seamlessly with your employee data and automatically populate for every send. No spreadsheet gymnastics. No manual editing. Just better subject lines, faster.

You can even pair merge tags with sender personalization (like ghostwriting on behalf of managers or team leads) to further boost employee engagement. After all, people are more likely to open a message from someone they know.

Feeling stuck? Let AI suggest subject lines that work

Even the best communicators get writer’s block sometimes. You know what the message needs to say, but that subject line? It’s just not clicking. You’re staring at the blinking cursor, wondering if “Important update” is boring (it is) or if you can get away with a pun (probably not).

If you’re struggling with how to write internal email subject lines, our built-in AI suggestions can make the process quick and easy. Unlike most AI tools that require prompt writing or tedious context copy-pasting, Workshop’s AI suggestions are built right into your workflow. Once your internal email is written, Workshop will review the content of your email and provide a list of subject lines and preview text that match the content and tone of your email.

Think of it like having a brainstorming buddy who is really good at writing subject lines (and sounds just like you!). You still make the final call, but AI gives you a fast, fresh batch of ideas to react to. No overthinking. No back-and-forth Slack messages to your team. Just usable, human-sounding options you can test and tweak. This is especially handy when:

• You’re in a rush and need inspiration, fast
• You’re trying to avoid using the same subject line every week
• You want to A/B test without writing everything from scratch
• You’ve written the perfect email body and just need a solid hook

And because it’s native to Workshop, there’s no risk of your internal message being interpreted like a marketing email. Everything stays on-brand, relevant and appropriate for your employees. You’ll never have to settle for “Monthly update” again.

Pro tip: Need to tweak your messaging or optimize a message for a different channel? Our built-in AI capabilities aren’t just good at subject lines and preview text — you can also use it to improve voice and tone, fix spelling or grammar issues and even adapt the content of your email for Slack or Teams. No matter where you’re sending, with Workshop’s AI tools, it’s simple to create polished and professional communications in no time at all.

Don’t guess, test: how to learn what works (and what doesn’t)

You wouldn’t send an important company-wide message without proofreading it. So why would you send it without knowing if the subject line is actually effective? Testing isn’t just for marketing teams anymore. Internal comms teams that treat subject lines as an experiment (instead of a fixed task) see better results over time. And that’s because testing gives you real insight into what resonates with your audience.

Start small. A/B test two different subject lines for the same message. Try one that’s straightforward and one that’s a little more playful. Workshop makes this easy with built-in campaign analytics, so you can track and improve internal email open rates by subject line, sender, time, department and more. And because our analytics dashboard is built specifically for internal comms, you can spot trends at a glance, without needing to dig through complex reports or export raw data. It’s fast, intuitive and designed for teams that need insights, not information overload.

Here’s what to pay attention to as you test:

• Open rate trends over time: Are your rates improving or stagnating?
• High-performing senders: Do emails from managers or execs get better engagement?
• Best send days/times: (Spoiler: Wednesday at 9 AM is your sweet spot, according to our data)
• Tone and style: Do questions work better? What about urgency? Emoji use?

Testing doesn’t need to slow you down. In fact, it can be baked into your existing workflow. Just pick one variable to experiment with in each email: the subject line length, the inclusion of personalization or even the emoji. And see what moves the needle.

Best of all, Workshop lets you compare subject lines over time, so you can build a bank of “greatest hits” and avoid reinventing the wheel every week. Bottom line: The more you test, the better your emails perform. And the better they perform, the more informed (and appreciated) your employees feel.

That’s a wrap (now go write better emails)

We get it. Subject lines can feel like the smallest part of your internal emails. But they often carry the biggest weight. They’re not just labels. They’re invitations. And when done right, they’re the difference between something being “marked as read” and “actually read.”

Too often, internal comms teams pour hours into crafting thoughtful messages only to lose the audience at hello. That’s where strong subject lines come in. They help you cut through the noise, set the tone and show employees that what’s inside is worth their time.

And don’t go it alone. Workshop’s tools, like AI-generated subject line suggestions, merge tags and built-in testing, are designed to make great email writing easier. So go ahead, give your subject line the attention it deserves.

Next up:
Ready to dig deeper? Subject lines are just the beginning. Explore all the ways Workshop helps internal comms teams thrive. Plus, download our 2025 Internal Communication Benchmarks & Best Practices Report to see how your internal emails stack up against the data and help elevate your internal comms. You’ll get insights into what’s working (and what’s not) across dozens of industries, plus practical tips to improve your strategy, boost engagement and build a more connected workplace.