Open rate is the percentage of emails that have been opened out of the total number of emails sent. It is calculated by dividing the number of emails opened by the number of emails sent and multiplying by 100.
Open rate is an important metric for email marketing as it gives an indication of the effectiveness of the subject line, sender name, and other factors that influence whether the recipient opens the email.
A good open rate is typically considered to be above 20% for most email campaigns.