Test your email subject line before you hit send. Get a score, see how it looks in a phone inbox, and get tips to improve it.
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What the tester checks
- Length: phones usually show about 35 to 45 characters, so keep the key words first. 30 to 50 characters works well for most emails.
- Spammy words: phrases like “free”, “act now” or “100% guaranteed” can look pushy and may hurt deliverability.
- ALL CAPS and !!!: they read like shouting.
- Emojis: one can help an email stand out; several can look cluttered.
- Preview text: the line shown after the subject in most inboxes.
- Fake Re: or Fwd: misleading subject lines can break marketing rules.
Before and after
| Before | After |
|---|---|
| FREE!!! Act NOW to WIN cash 🔥🔥🔥 | Your November order: 3 ideas to save time this week |
| Newsletter #42 | 5 quick recipes for busy weeknights |
| Don’t miss out | Last day: 20% off winter coats ends at midnight |
Tips for better subject lines
- Be specific: numbers, dates and names beat vague promises.
- Match the subject to what’s inside, so people trust your emails.
- Use preview text to add a second reason to open.
- A/B test two versions on part of your list, then send the winner.
Whether your email lands in the inbox depends mostly on your sender reputation and how engaged your list is, not just your subject line.
Frequently asked questions
What is a good length for an email subject line?
About 30 to 50 characters. Put the most important words first, because phones cut off longer lines.
Do spam trigger words still matter?
Modern filters focus more on sender reputation, but pushy wording can still hurt opens and trust.
Should I use emojis in subject lines?
One relevant emoji can work well. Test it with your audience.
What is preview text?
The short line after the subject in the inbox. If you don’t set it, the inbox shows the first words of your email.
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