Subject Lines Are the Gate to Every Email

An email that isn’t opened earns zero revenue. The subject line determines whether your carefully crafted email is read by 40% of your list or 12%. The difference between a 20% open rate and a 40% open rate — all else equal — doubles the revenue from every email send. Subject line testing is the highest-leverage copywriting task in email marketing, because a single word change affects every send forever.

The Psychology Behind High-Open Subject Lines

  • Curiosity — creates an information gap the reader must close by opening. “The email we didn’t want to send” or “This is unusual for us”
  • Self-interest — makes clear what benefit the reader receives. “Your cart just got cheaper” or “Save 20% — 4 hours only”
  • Urgency/scarcity — triggers loss aversion. “Last 12 hours” or “Only 3 left at this price”
  • Social proof — triggers FOMO. “3,842 customers bought this in the last 7 days”
  • Personalisation — seeing your name increases open rate by 26%. “[First name], this is for you”

20 Abandoned Cart Subject Lines

  • “You left something behind”
  • “Still thinking about it?”
  • “Your cart misses you”
  • “[Product name] is waiting for you”
  • “Before it sells out…”
  • “Did something go wrong at checkout?”
  • “Your [product] is running low on stock”
  • “Complete your order — we’ll give you 10% off”
  • “Don’t let this one go”
  • “We saved your bag — but not for long”
  • “Is this the one you want, [first name]?”
  • “Quick question about your order”
  • “Your cart expires tonight”
  • “Still interested? Here’s 10% off”
  • “[Product name]: here’s what others think”
  • “One step away from [benefit of product]”
  • “Your [product] has been put on hold”
  • “Hurry — popular items sell out fast”
  • “We noticed you were checking out [product]”
  • “Last chance to grab [product name]”

15 Welcome Email Subject Lines

  • “Welcome to [Brand] — here’s your 10% off”
  • “You’re in. Here’s what happens next”
  • “[First name], welcome to the family”
  • “Your exclusive welcome offer is inside”
  • “We’re glad you found us. Here’s why”
  • “The [Brand] story — and why it matters to you”
  • “Everything you need to know about [Brand]”
  • “Your welcome gift is waiting”
  • “3 things our best customers love about [Brand]”
  • “Meet the brand [publication] called ‘game-changing'”
  • “Before you shop, read this”
  • “Welcome — and here’s what sets us apart”
  • “You joined [number] subscribers. Here’s your reward”
  • “Start here — our most popular products”
  • “[First name], you qualify for free shipping today”

15 Promotional Campaign Subject Lines

  • “20% off — 48 hours only”
  • “The sale our accountant hates”
  • “Biggest discount we’ve ever offered”
  • “[First name], your exclusive offer is live”
  • “This doesn’t happen often”
  • “New arrivals — and they’re selling fast”
  • “[Product category] under £25”
  • “We don’t do this often: 30% off everything”
  • “Your early access starts now”
  • “Members only: 25% off before public launch”
  • “Flash sale — 3 hours to shop”
  • “The [season] edit is here”
  • “Prices drop at midnight”
  • “[Number] of our best products, on sale today”
  • “Shop before [specific date/event]”

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