Email subject lines that get opened (and the ones that don’t)

The subject line has one job: get the email opened by someone who'll be glad they did. Not tricked. Glad. Here's what works.

The rules

• Say what's inside. "Your boiler's annual check" beats "Don't miss out!"
• Keep it short. Under about 50 characters, so it isn't cut off on a phone.
• Sound like a person. Write it the way you'd text a customer.
• Be specific. Numbers, names, dates. "3 things to check before winter" beats "Winter tips".
• One idea. If you need "and", you have two emails.

Examples to steal

For a newsletter:

• Before the first frost: 3 things to check
• We're open Saturdays now
• The question everyone asked us this month

For a follow-up:

• Your quote for the kitchen rewiring
• Quick question about Thursday
• Did the new tap fix it?

For a reminder:

• Invoice #0193, due Friday
• Your appointment tomorrow at 9

What gets ignored (or spam-foldered)

• ALL CAPS and !!!
• "Free", "Act now", "Limited time" stacked together. Spam filters have opinions about those, and so do people.
• Fake replies, like "Re:" on an email that isn't a reply. It works once, then they stop trusting you.
• Clever puns nobody gets in a three-second glance at their inbox.

Test it on yourself

Read your subject line out loud and ask: if this arrived from someone I barely knew, would I open it? If you hesitate, make it plainer.

(My own subject lines are mostly "MEOW" and "MEOW!!!". Do not take notes from me on this one.)