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Will your cold email subject line get opened?
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40 characters · 6 words
75/ 100
Subject-line score
Okay
Decent — a couple of tweaks will lift it.
How it lands on mobile
A
Alex Rivera9:41 AM
quick idea for {{company}}'s Q3 pipeli…
Hi there — saw you just expanded the team and wanted to share…
What to fix
- Broken personalization token. A merge tag like {{firstName}} shipped un-rendered screams “mass blast.” Make sure your tool fills it — or remove it.
What’s working
- Good length — won't get cut off on mobile
- Concise (3–7 words)
- Includes a specific number
A great subject line gets the open. Komo makes sure the whole email is worth replying to.
See KomoHow the subject line tester works
1. Paste or generateDrop in a subject line to test, or describe your email and let AI draft a few angles for you.
2. See the scoreGet an instant 0–100 score with the exact issues — spam words, length, caps, emoji, broken merge tags.
3. Check the mobile cut-offPreview how it lands in a real inbox so the part that matters isn't truncated on a phone.
What makes a cold email subject line work
Four rules the scorer checks for you — the difference between the inbox and a deleted-unread.
Keep it 3–7 words, under ~50 charactersMore than half of cold emails are opened on a phone, where the subject is cut off around 35–40 characters. Front-load the words that matter and drop the rest.
Be specific, not cleverA concrete hook — a result, a number, a trigger you noticed — beats curiosity-bait with a busy B2B buyer. Vague or clickbait lines read as mass mail.
Write it like one human to anotherSentence case, no ALL CAPS, no emoji, at most one (ideally zero) exclamation marks. Title Case Every Word and hype punctuation both scream marketing blast.
Personalize for real — or not at allA relevant reference earns the open; a merge tag that ships as “Hi {{firstName}}” kills it. If you can't personalize cleanly, a plain specific line wins.
Cold email subject line examples
Avoid🚀 ACT NOW — Limited Time FREE Demo!!!
Emoji, ALL CAPS, spam words (“free”, “act now”, “limited time”), and triple exclamation — a filter magnet.
Betteridea for cutting your SDR ramp time
AvoidRe: our conversation
A fake “Re:” you never had erodes trust the second they open it.
Betterquestion about your Q3 outbound
AvoidRevolutionize Your Entire Go-To-Market Motion Today
Too long (truncates on mobile), Title Cased, and hype with no specifics.
Bettersaw you're hiring 3 AEs
Cold email subject line questions, answered
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