
Read Rate (deliverability)
Read rates are a metric that you typically see in deliverability monitoring programs such as Inbox Tracker by Sparkpost (formerly eDatasource) and Validity (formerly Return Path). This metric is similar to the open rate but with a crucial difference in how they are measured. A Read event is measured (or counted) when a subscriber marks

Engagement Time
Image courtesy of Email on Acid Email Engagement is sometimes referred to as Engagement Time or Read Time in certain tools and it measures the amount of time that an email is engaged with by the recipient. Similar to opens, this metric is measured using a tracking pixel; each second the email is open the

Render 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, ClicktoOpen 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

Click Reach Rate
Click Reach Rates are between 0% and 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100. Unlike Clickthrough Rate, which gauges performance on a single email message, Click Reach Rate shows you what unique percentage of your list clicked on at least one of a series of email

Open Reach 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, ClicktoOpen 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

Conversion Rate from Click
This metric takes a value of between 0 and 1, by dividing the number of conversions by clicks and is typically expressed as a percentage of 0 to 100%. Higher is better in the range of values, and all senders like a high conversion rate. This is the conversion rate at the bottom of

Conversion Rate from Sent
Conversion Rate from Sent is the conversion rate based upon “delivered” emails, with a value between 0 to 1 typically expressed as a percentage of 0% to 100%. Higher is better, and senders generally want their conversion rate to be as high as possible. However, the highest conversion rate is not always the best. Sometimes

Revenue per Email Sent (RPE)
RevenueperEmailSent (RPE, often called “Revenueperemail”) is measured as a currency value; it can be as low as $0 and there is no upper limit on how high it can be. It is more easily calculated than ReturnonInvestment (ROI) or ReturnonAdSpend (ROAS), as the only data required is the revenue generated and the number of emails

Return on Ad Spend (ROAS)
Return on Ad Spend (ROAS) can be a positive or negative value (and becomes a percentage when multiplied by 100). This metric has been “borrowed” from the advertising industry. ROAS has a slightly different meaning when it comes to email marketing (for the advertising industry, the “marketing cost” above would be “advertising cost”). In general,

Deliverability or Inbox Placement Rate
Inbox Placement Rates (IPR) are between 0% to 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100. Tips for interpreting Inbox Placement Rates: Inbox Placement Rates are meant to show the percentage (or fraction) of emails that were delivered to the inbox rather than the spam or junk

Spam Complaint Rate
Spam Complaint Rates are between 0% to 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100. Actions contributing to your spam complaint rates occur when a recipient clicks on the “This is Spam” (TiS) button in their email client. If the Mailbox Provider (MBP) has a feedback loop

Unsubscribe Rate
Unsubscribe Rates are between 0% to 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100. Tips for interpreting Unsubscribe Rates: Unsubscribe rates are meant to show the fraction (or percentage) of people that have taken an active measure to disengage with your email program by clicking on the

ClicktoOpen Rate (CTOR)
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, ClicktoOpen 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

Clickthrough Rate (CTR)
Clickthrough Rates (CTR) are between 0% and 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100. Unlike Open Rates, CTR is an absolute metric — if someone clicks, it is counted here; there is no way to click and not have it recorded. A higher CTR is usually

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, ClicktoOpen 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

Return on Investment (ROI)
Return on Investment (ROI) can be a positive or negative value (and becomes a percentage when multiplied by 100). ROI is a metric used in a variety of industries to understand the results of an investment. Similar to Return on Ad Spend (ROAS), the HIGHER the ROI, the better. Unlike ROAS, ROI does represent the

Delivery Rate
Delivery Rates are between 0% to 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100. Tips for interpreting Delivery Rates: Delivery rates are meant to show the percentage (or fraction) of emails that were delivered successfully to recipients. In general, the HIGHER the delivery rate, the better. A

Bounce Rate
Bounce Rates are between 0% to 100%; once you finish the equation, turn your answer to a percentage by multiplying by 100. Tips for interpreting Bounce Rates: Bounce rates are meant to show the fraction (or percentage) of emails that could not be delivered successfully to recipients. There are two main categories of bounces: A