Open Rate


Apple’s Mail Privacy Protection Initiative which is included with iOS 15 and is expected sometime in the fall of 2021 will impact Open Rate, Click-to-Open Rate, Open Reach Rate and Render Rate for users reading mail on Apple Mail. The information here may change and we will update it when we know more. To learn more visit the Only Influencers Pixelgeddon Resources Page.

Open Rates are between 0% to 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100.

In general, the HIGHER the open rate, the better. However, high Open Rates don’t fully tell the story of an email’s success, nor do low Open Rates mean an email was a complete failure. 

Tips for interpreting Open Rates:

Open rates are meant to show the fraction (or percentage) of people that open a particular email — however, the methods used to track if an email has been opened aren’t perfect. (For more on this see, “Email Opens: What Are We Actually Measuring?”) When you are looking at Open Rates, remember that the reported number of opens could be overcounted or undercounted for a variety of reasons. Open rates are often more powerful to compare across emails than to use on their own. 

See our other articles for examples of metrics that aren’t as susceptible to over or under-reporting, like Click-through Rate and Conversion Rate from Sent. 

In summary, you use open rates to help optimize your email campaigns:

  • Compare how emails compare when sent to a similar list,
  • Evaluate the performance of an email program over time

Avoid only looking at open rates when you are evaluating a single email. And be very cautious when comparing Open Rates from different ESPs.  Some ESPs use unique opens when calculating the Open Rate (as we have described above) while other ESPs replace the unique number of opens with the total number of opens when calculating the Open Rate. 

Related Links:

Curious about how emails are marked as open? Check out “Email Opens: What Are We Actually Measuring?”  and Understanding Marketing Metrics: Email Open Rates

Looking to test your emails to see what will increase your Open Rates? Check out this article on the OI blog: Test your way to better Open Rates.

Open Rate often measures subject line success; however, this great article from Litmus shows us otherwise: “Why Measuring Subject Line Success by Opens Is All Wrong.”

Not sure if Open Rates are right for you? There are some that would argue that open rates aren’t worth your time. To learn more, check out these articles: