Email Subject Line scoring
Score your subject line before you hit send
The subject line decides whether your email gets opened or archived. Lytms evaluates curiosity, specificity, length, preview text fit, and personalization signals.
Free with Google or email. No credit card required.
What Lytms evaluates
Every email subject line is scored across platform-specific dimensions. Each dimension gets a 1-10 score with quoted evidence and a concrete rewrite.
does it earn the open with curiosity or specificity?
do the first 2 sentences justify the open?
is the email scannable, with short paragraphs and bold key phrases?
is there exactly one ask, stated as an outcome?
does it reference the recipient's situation, not just their name?
can the reader get the point in a 5-second skim?
Email Subject Line best practices
Patterns from high-scoring email subject lines. Apply these before you score for higher baseline results.
Keep subject lines between 28 and 50 characters
Mobile inboxes truncate at roughly 35-40 characters. Desktop shows more, but the first 28 characters are what decide the open. Front-load the most compelling element.
Use curiosity or specificity, never both at once
"Your pipeline forecast is wrong" creates a curiosity gap. "67% of sales leaders miss quarterly targets" uses specificity. Combining them ("67% of your forecasts might be wrong") dilutes both signals.
Write the preview text as a continuation, not a repetition
Most email tools let you set preview text separately. Use it to complete the thought the subject line started, not restate it. The preview text is your second headline — use it to close the curiosity gap enough to justify opening.
One email, one ask, one CTA
Emails with multiple CTAs convert less than emails with one. Every link competes with every other link. Pick the single most important action and make it unmissable.
Avoid spam trigger patterns, not just spam words
All caps, excessive punctuation (!!!), and "FREE" in the subject line are obvious. But long link-heavy emails, image-only emails, and emails that re-use the subject line as the first sentence also trigger filters.
Frequently asked questions
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