The percentage of email recipients who open a given email, calculated as opens divided by emails successfully delivered.
Why it matters
Open rate is a primary indicator of subject line and sender reputation strength — though it's become a less precise metric in recent years as privacy features in some email clients can register an "open" automatically without a person actually reading the email.
In a sentence
"Open rate held steady even after we changed the subject line format, so that wasn't the lever affecting performance."
Related terms
- Often confused with: Click rate (open rate measures whether the email was opened at all; click rate measures whether the reader then clicked a link inside it).