Email click-through rate (CTR) is the percentage of clicks on links included in your email content.  It is calculated as the (total number of clicks/the number of emails delivered) x 100.  Email click-through rate is a crucial metric to know how your content performs after it reaches the email boxes of the recipients.  The click-through rate does not include bounced emails.  Hence you will have to take only the delivered emails into acount while calculating click-through rates.  

Example:  If the emails delivered are 1000 and the number of clicks on links is 70, then CTR would be

(70/1000) x 100 = 7

Emails sent from an email marketing solution helps you improve your click-through rates.