The Opened” rate is calculated by taking into account all the emails that are accepted and read by the recipient.
Generally speaking, a good range of “Open” rate is between 15% and 25% for marketing emails, and between 30% to 40% for transactional emails.
Each business sectors open rates are different so we would recommend that you learn the open rates for your particular industry.
Please remember that good subject lines are important as this is what encourages the recipient to open your email campaign.