It still surprises me how many seasoned email marketers analyze their email performance without knowing the formulas behind the basic metrics. For me, it has always been helpful to understand these metrics calculations, because understanding the specifics of the matter gives me a better view of the whole picture. So let's consider these email formulas in sequence of action.

When you send out an email campaign, first you look at the <b>delivery rate</b> - how many email messages either made it into the inbox or junk box. This is calculated by taking the number of messages delivered divided by the number of email list members you attempted to send to.

<b>Delivery Rate = Delivered / Attempted Sends</b>

Next, if you want to calculate your <b>bounce rate</b>, take the number of bounces and divide it by the number of email list members you attempted to send to.

<b>Bounce Rate = Bounced / Attempted Sends</b>

Once the email is delivered, you want to know what your open percentages are. So take the number of opens and divide it by the number of messages delivered. Consider here the difference between aggregate (total) and unique opens:

• The <b>aggregate open rate</b> includes every instance the message is opened, even by the same person; it is possible that your aggregate open rate is larger than your delivery rate.

<b>Aggregate Open Rate = Aggregate Opens / Delivered</b>

• The <b>unique open rate</b> counts the number of unique individuals who opened your message - for example, if John Doe opened your email ten times, it would only count as one unique open.

<b>Unique Open Rate = Unique Opens / Delivered</b>

<b>Click-through rates</b> are calculated in a similar fashion to open rates, considering aggregate versus unique clicks. Take the number of aggregate or unique clicks and divide it by the total number of email messages delivered.

<b>Aggregate Click-through Rate = Aggregate Clicks / Delivered</b>

<b>Unique Click-through Rate = Unique Clicks / Delivered</b>

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