If you’ve ever hesitated before hitting “send” on a marketing email—wondering whether that subject line should be Capitalized, all lowercase, or even ALL CAPS—you’re not alone.
I was talking to a client on our monthly check-ins recently and they asked me for advice on an email campaign they had drafted. While I wasn’t running email campaigns for them, I was thrilled that they asked because I think that business owners often focus (rightfully so) on getting leads in the door. While this is vital, it can unfortunately lead to a neglect on the lead nurturing side. After all, you can have infinite leads—but if your lead nurture and sales processes aren’t set up for success, good luck converting them into clients and customers. One tactic I often recommend is sending mid-cycle marketing emails, which are designed to re-engage warm leads during the in-between stages of your sales funnel. (Not sure what those are? Here’s a breakdown of what a mid-cycle marketing email is.) But I digress… my client wanted to know if they should be capitalizing their email subject lines. This is a great question because subject lines aren’t just formatting choices—they’re your first impression, and they directly impact open rates, deliverability, and brand perception.
So, let’s dive right in:
The Short Answer: It Depends on Your Brand—and Your Audience
There’s no one-size-fits-all answer when it comes to capitalization in your emails. But here’s what I’ve seen in my testing and experience as a Massachusetts digital marketing consultant:
Title Case (Capitalizing Major Words)
Example: This Is Your Last Chance to Register for the Webinar
- Professional, polished, and clear
- Great for B2B, high-trust industries, or formal promotions
- Gives a sense of importance or urgency
Use it when:
You want your email to feel official, trustworthy, or event-related. This is great for professional services firms such as law firms, accounting firms, and other industries where strict adherence to grammar guidelines is not only preferred but expected. In my work, this is generally the standard that I default to unless the email is for a company with a more personal brand.
I love to copy and paste my email subject line into https://capitalizemytitle.com/ to ensure that I have followed the appropriate guidelines. Whether you want to use APA, Chicago, or MLA, this tool can format your subject line perfectly. Note: I don’t receive any kickback from recommending this tool: it’s just genuinely something that I use every day and it’s free so I want to share the wealth.
Sentence Case (Only the First Word Capitalized)
Example: Don’t miss our new marketing guide for 2024
- Feels friendly, modern, and conversational
- Can work well for B2C, newsletters, and community engagement
- Easy to read on mobile
Use it when:
You’re aiming for a casual, approachable tone and want to mimic a personal email.
I honestly don’t love this option and rarely use it because I feel like it can get easily lost in a sea of emails. If you’re going to use this in anything but B2C, I believe it should be with a specific branding in mind and you should really consider whether all lowercase, APA style (above), or another style may be more appropriate. If you do use it, try building suspense by ending the email subject line in an ellipses.
Feeling the tension yet…?
ALL CAPS (Be Wary)
Example: LAST CHANCE TO SAVE BIG!
- May trigger spam filters
- Often reads as shouting- which can work when used sparingly but can also be over the top
- Can hurt brand trust if overused
Use it sparingly for a single word like FREE or NEW, but avoid full subject lines in all caps.
What Actually Impacts Open Rates More Than Capitalization?
While formatting matters, what impacts open rates even more is:
Relevance: Are you sending the right message to the right person at the right time?
Clarity: Is it clear what the reader will get when they open?
Curiosity: Does the subject line make them want to know more without being clickbait?
Tone: Does it sound like you and match your brand’s personality?
Joyce Voice Pro Tip: Test It. Then Test It Again.
Don’t guess—test. Run A/B subject line experiments with different capitalization styles and track open rates.
What performs best for a startup SaaS company might flop for a nonprofit. At Joyce Voice, I help clients run data-driven email campaigns that not only get opened, but also drive engagement and conversions. Because I’ve worked with clients in a variety of industries and done a lot of testing already, I can help steer your campaign in the right direction or design one from scratch to give you a better chance of success.
So, Should You Capitalize Your Email Subject Lines?
-If your brand is professional and polished, go with Title Case and consider using a tool like https://capitalizemytitle.com/ to make sure you’ve got the titling correct.
-If your brand is casual and personal, opt for Sentence case
-Avoid ALL CAPS unless you’re making a very intentional stylistic choice
And no matter what—make it relevant and compelling
Want Help Crafting Emails That Get Opened?
At Joyce Voice, we specialize in strategic email marketing that aligns with your voice and drives real results. We partner with a select group of organizations to run strategic campaigns, refine messaging, boost performance, and build lasting community connections.
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