How to Write Email Subject Lines That Get Opened
Your subject line determines whether your email gets opened or ignored. Here are the formulas that actually work for small businesses.
2 min read · Updated 2026-04-15
Short answer
The best subject lines are specific, create curiosity or urgency, and feel like they're from a real person — not a marketing department. Short beats long. Personal beats corporate.
Subject line formulas that work
The direct benefit: "How to get 10 Google reviews this week"
The curiosity gap: "The website mistake costing you customers"
The question: "Are you making this SEO mistake?"
The number: "7 ways to grow your email list without ads"
The personal: "Quick question for you, [first name]"
The urgent: "Last chance — offer ends tonight"
What kills open rates
- All caps: "HUGE SALE THIS WEEKEND" — feels like spam
- Too vague: "Newsletter #47" — no reason to open
- Too long: Most email clients cut off after 50 characters on mobile
- Clickbait: "You won't believe this..." — people are over it
- Spam trigger words: "FREE", "Act now", "Limited time offer!!!" — land in spam folder
Length and formatting
- Aim for 30–50 characters (6–10 words)
- Use lowercase or sentence case — not Title Case Every Word
- Emojis can help if used sparingly and relevant (not random)
- A/B test two versions if your email tool supports it
The preview text matters too
The preview text (shown in the inbox below the subject line) is your second chance to get the open. Make it complement — not repeat — the subject line.
Subject: "The SEO mistake costing you traffic" Preview: "Most small business owners make this without knowing"