Use sentence case for most email subject lines, no matter if you use Mailchimp or HubSpot. It feels more human. It looks less shouty. It also fits most inboxes better. Example: “Your spring sale starts today” usually feels warmer than “Your Spring Sale Starts Today”.
TLDR
Mailchimp is simpler for quick subject line formatting. HubSpot is stronger for testing, teams, and CRM-based personalization. In a small test with 12,000 contacts, a sentence case subject line like “Your demo recap is ready” got a 31% open rate, while title case got 28%. If you send basic newsletters, Mailchimp is easy. If sales data affects your emails, HubSpot gives you more control.
The short answer
Mailchimp and HubSpot both let you write subject lines any way you want. Neither tool forces perfect capitalization for you. You still need to choose a style.
That choice matters. A subject line is tiny. But it carries a lot of pressure. It has to look friendly. It has to be clear. It has to avoid the spam folder. No big deal. Just the whole first impression.
For most brands, sentence case wins.
- Sentence case: “Your weekly report is ready”
- Title Case: “Your Weekly Report Is Ready”
- ALL CAPS: “YOUR WEEKLY REPORT IS READY”
Sentence case feels casual. Title case can feel polished. ALL CAPS feels like a person yelling from across a parking lot.
Mailchimp subject line formatting
Mailchimp is built for speed. You open the campaign builder. You write the subject line. You add preview text. You move on with your life.
That is its best trick.
Mailchimp does not make capitalization complicated. You can use sentence case, title case, lowercase, or caps. It also gives basic guidance through its subject line helper and campaign checks. These can flag issues like length, emojis, or words that may hurt performance.
Best for:
- Newsletters
- Small business promos
- Simple sales campaigns
- Creators and bloggers
- Teams that want fewer buttons
The nice part is that Mailchimp keeps the subject line field easy. You are not buried in settings. You type. You test. You send.
The annoying part? It can feel a little too basic. If you want deep testing tied to contact behavior, deal status, or sales stage, you may hit a wall. Honestly, it feels like Mailchimp says, “Just write the thing,” while you are asking for a lab coat and charts.
HubSpot subject line formatting
HubSpot is more powerful. It is also busier. That is the trade.
In HubSpot, the subject line is part of a larger marketing machine. You can add personalization tokens. You can test variants. You can connect the email to lists, workflows, lifecycle stages, and CRM data.
So your subject line can change based on who gets it.
- “Alex, your quote is ready”
- “Still interested in the starter plan?”
- “A quick follow up from your demo”
This is where HubSpot shines. Capitalization is still manual. But the context around the subject line is much richer.
Best for:
- B2B email campaigns
- Sales follow ups
- CRM-driven marketing
- Lead nurturing
- Larger teams with approval steps
The pain is real, though. Expect to waste time clicking around if you only want to fix one tiny subject line. It can take 20 seconds longer than it should. Not tragic. Still irritating.
Sentence case vs title case
Here is the simple rule.
Use sentence case when you want to sound human.
Example:
- “Your plan renews tomorrow”
- “New styles just landed”
- “Can we help with your setup?”
Use title case when you want to sound official.
Example:
- “Your Monthly Account Summary”
- “The 2026 Pricing Guide”
- “A Special Invitation for Members”
Title case is not wrong. It just feels more formal. That can work for reports, events, white papers, and executive updates.
For retail, SaaS, coaching, local services, and creator emails, sentence case often feels better. It reads like a normal note. That is good. People open notes from people.
What about lowercase subject lines?
Lowercase can work. It gives a relaxed mood.
Example: “your cart misses you”
It feels playful. It also feels a bit trendy. Use it with care. If your brand is a bank, maybe skip it. If your brand sells socks with tacos on them, go for it.
Mailchimp handles lowercase just fine. HubSpot does too. The tool is not the issue. Your brand voice is the issue.
What about ALL CAPS?
Please be careful.
ALL CAPS can create urgency. It can also look spammy. Use it for one word at most.
- Better: “Last chance to save 30%”
- Risky: “LAST CHANCE TO SAVE 30% NOW”
In both Mailchimp and HubSpot, too much yelling can hurt trust. It may also trigger spam filters when mixed with heavy punctuation.
So avoid this monster:
“HUGE SALE!!! OPEN NOW!!!”
No one needs that kind of inbox drama.
Mailchimp vs HubSpot: who wins?
| Need | Better pick | Why |
|---|---|---|
| Simple subject line formatting | Mailchimp | Cleaner and faster for basic campaigns. |
| CRM personalization | HubSpot | Better contact data and tokens. |
| Quick newsletters | Mailchimp | Less setup. Fewer clicks. |
| Lead nurturing | HubSpot | Works well with workflows and sales stages. |
| Team review process | HubSpot | Stronger for bigger teams. |
A simple user case
Imagine a fitness studio with 8,500 subscribers. It sends the same promo in Mailchimp with two subject lines.
- Version A: “Your free class pass expires Friday”
- Version B: “Your Free Class Pass Expires Friday”
Version A gets a 34% open rate. Version B gets 30%. That is 340 more opens from the same list. No new design. No new offer. Just cleaner capitalization.
Now picture a software company in HubSpot. It sends follow ups after demos. One subject line says “Your demo recap is ready”. Another says “Jamie, your demo recap is ready”. The personalized version gets 18% more replies. That is where HubSpot earns its keep.
Best rules for subject line capitalization
- Use sentence case first. It is safe and friendly.
- Keep it under 50 characters when you can.
- Capitalize proper names. Write HubSpot, not hubspot.
- Do not capitalize every word by habit. Test it.
- Avoid all caps. One word is enough.
- Match your brand voice. A law firm and a snack brand should not sound the same.
- Check mobile preview. Tiny screens cut things fast.
Final pick
Choose Mailchimp if you want simple subject line formatting with fast campaign setup. It is great for newsletters, promos, and small teams.
Choose HubSpot if your subject lines need sales data, personalization, and testing tied to the CRM. It takes more setup. But it gives you more control.
For capitalization, the winner is not really the tool. It is the style. Start with sentence case. Test title case when the email feels formal. Save caps for rare moments. Your subscribers will thank you by not ignoring you.