Email Open Rate
Email Open Rate is a measure used by marketers of how many people ‘view’ or ‘open’ the email they send out. Open rate is tracked using a transparent 1x1 pixel, or small transparent tracking image, that is embedded in outgoing emails. When the browser used to display the email requests that image, then it is recorded as ‘open’ for that email by the image's host server. The email will not be counted as an open until one of the following occurs:
The recipient enables the images in the email or
The recipient clicks on the link in the email
The Email Service Provider calculates the open rate by dividing the number of emails opened by the number of emails that were sent to the recipients ( excluding the number of bounces ). Emails that have bounced or not delivered cannot be considered in the equation as they will not be opened anyway.
Email open rates are not 100% accurate as the rates can be under or over reported. If the receiver has a preview pane and the email automatically displays ( therefore, images may be downloaded too ) without the recipient actually viewing the email or clicking any link in the email. If you are sending text-only emails, there is no way to record open rates, unless the receiver actually opens the link. Similarly, if the HTML email is viewed without the images showing up, it will not be recorded as ‘open’.