Introducing the Email Subject Line Tester — Score Before You Send

The subject line decides whether your email gets opened at all, and readers judge it in a fraction of a second. The new Email Subject Line Tester scores your line from 0 to 100 as you type, so you can fix the obvious problems before you ever hit send.

What it does

• Live score: a 0–100 rating that updates with every keystroke.
• Length check: flags lines outside the ~30–50 character sweet spot that survives inbox truncation.
• Spam-word detection: spots triggers like “free”, “buy now”, “winner”, and ”$$$”.
• Emoji and ALL CAPS: counts emoji and detects shouting, both of which can sink deliverability.
• Power and urgency words: rewards the wording that genuinely lifts opens.
• Suggestions + open-rate hint: concrete fixes and a sense of where the line stands.
• Client-side: nothing you type leaves your browser.

Why it matters

You can write a great email and still get ignored if the subject is too long, too spammy, or reads as shouting. Catching those issues takes seconds with a quick pre-send check — and it means your A/B tests compare genuinely strong lines instead of rediscovering that “FREE $$$ ACT NOW” performs badly.

Learn more

Read Writing Email Subject Lines That Get Opened, then try the Email Subject Line Tester on your next campaign.