Email Subject Line

An email subject line is an introduction to your email. It is the first text readers see in the inbox, along with the email preheader. It is the most important part of email marketing strategy for three reasons:

  1. It’s the first impression. If it’s in an email sequence, the earliest emails’ subject lines are the most critical.
  2. If it doesn’t entice an open, your email content goes unread. These negative engagement signals can hurt your deliverability.
  3. Through A/B testing, your email subject lines can be optimized time and time again for better results.

What is the subject line in emails?

The best email subject lines represent the email in 40 – 60 characters. Long subject lines aren’t necessarily bad as long as they’re specific and customized to email recipients. The longest length visible is ~45 characters for mobile devices and ~95 on desktops.

The subject line of email campaigns affects at least these three metrics:

  • Email open rates, both for the specific email and the rest of the email sequence
  • Conversion rates, as it should attract more people to read the email, and eventually click on the call-to-action
  • Unsubscribe rate, because good subject lines can reduce spam reports, while generic ones may increase them

Note: To optimize open rates, complement your best subject lines with email preheaders, as they both show on the inbox up to ~120 characters.

Email Subject Lines Examples

The following examples have been checked with an email subject line tester:

  • 30 Catchy Email Subject Lines + How to Make Them
  • 💎 how to make the perfect email marketing campaign
  • Emails moved to the SPAM folder? Top 5 mistakes
  • Company Name, can you get even higher open rates? 3 ways to find out
  • 5 Sender Name Ideas To 🚀 Boost Open Rates

For more subject line ideas, here are 700+ headline templates you can try, plus a guide on how to write effective email subject lines.