What is an Open Rate?
The percentage of email recipients who open your email.
How Open Rate Works
Open rate measures the percentage of delivered emails that recipients opened. It's calculated by dividing unique opens by delivered emails and multiplying by 100. Open rate is one of the most common email marketing metrics, though its accuracy has decreased with privacy changes.
Apple's Mail Privacy Protection (MPP) pre-loads email content, artificially inflating open rates for Apple Mail users. This means open rates are now less reliable as an engagement indicator than they were historically. Despite these limitations, open rate still provides directional value for comparing subject lines, send times, and sender names. Focus on trends rather than absolute numbers, and combine open rate with click metrics for a fuller picture of engagement.
Frequently Asked Questions
What is an Open Rate?
The percentage of email recipients who open your email.
Open rate measures the percentage of delivered emails that recipients opened. It's calculated by dividing unique opens by delivered emails and multiplying by 100. Open rate is one of the most common email marketing metrics, though its accuracy has decreased with privacy changes.
Why is Open Rate important?
Open rate indicates whether your subject lines and sender reputation are compelling enough to break through inbox clutter. While less reliable than before Apple MPP, it still signals list health and brand recognition. Declining open rates often indicate list fatigue, poor targeting, or deliverability issues. Use open rate alongside click-through rate to understand both initial interest and content engagement.
How do you calculate Open Rate?
Open Rate = (Unique Opens ÷ Emails Delivered) × 100. For example, if you sent 10,000 emails, 9,500 were delivered, and 2,850 were opened, your open rate is (2,850 ÷ 9,500) × 100 = 30%.