Email Subject Lines: 80 Examples That Get Opened
How to write email subject lines that get opened, with real examples and the psychology behind what works.
Your subject line decides whether the email gets opened. This guide explains what makes a subject line work and gives you categories of examples to adapt for UK audiences.
The job of a subject line
A subject line is not a summary - it is a promise. Its job is to make the reader curious enough to open, while being honest about what's inside. Misleading subject lines might boost opens short-term but destroy trust and deliverability.
What actually drives opens
- Personal relevance: the reader recognises it's for them.
- Curiosity: an intriguing but honest hook.
- Specificity: concrete numbers and details beat vague claims.
- The sender: a recognised, trustworthy from-name matters most.
Subject line formulas and examples
| Formula | Example |
|---|---|
| Problem + promise | Your abandoned cart is waiting - 10% off today |
| Curiosity gap | The email we almost didn't send |
| Number-led | 5 mistakes killing your open rates |
| Urgency (genuine) | Ends tonight: free delivery on orders over GBP 30 |
| Personal | A note for [Name] about your recent order |
| Recognition | You've been a subscriber for a year - thank you |
UK-specific considerations
- Use British spelling (honour, organisation, colour) if relevant to your audience.
- Be careful with 'free' and 'urgent' in subject lines - they can trigger spam filters.
- Authenticity beats hype with UK readers; overly aggressive tactics feel off.
Test and refine
Subject lines are never 'right' - they're right for your list. Use A/B testing in your platform to compare subject lines on a sample before sending to everyone. Track opens, but remember opens only matter if the content delivers.
Tip
Write the subject line last, after you know exactly what the email delivers. This keeps the promise honest.
Frequently asked questions
How long should a subject line be?
Most readers see the first 40-60 characters on mobile. Keep your key words early and let the rest be a bonus.
Should I use emoji in subject lines?
Sparingly and only if on-brand. Emoji can help you stand out or look unprofessional - test for your audience.
Do caps and exclamation make more people open?
Often the opposite. All-caps and excessive punctuation look spammy and can hurt deliverability and trust.