Email Subject Line Tester
Live scoring against length, spam triggers, emoji weight, urgency words, personalization, and mobile truncation. Compare two subject lines side by side.
Subject A
0 chars · 0 wordsMobile: 0 visible
Inbox preview
A
Your BrandNow
Your subject appears here
Preview text appears here
Score
,
Checks
Subject B (optional A/B compare)
0 chars · 0 wordsMobile: 0 visible
Inbox preview
B
Your BrandNow
Your subject appears here
Preview text appears here
Score
,
Checks
Verdict
Type something to compare A vs B.
What we score
- Length: 30–50 chars sweet spot; mobile cuts at ~30–40.
- Word count: 5–9 words tends to win in benchmarks.
- Spam triggers: 60+ flagged words downgrade deliverability.
- Emoji weight: 1 emoji can lift open rate ~25%; 2+ hurts deliverability.
- Urgency / power words: 1–2 lift CTR; 3+ feels spammy.
- Personalization: {first_name}-style merge tags detected.
- Formatting: ALL CAPS & !!! penalized.