Open rate: This is the percentage of delivered email messages that have been opened.

Click-to-open rate (CTOR): This is  the percentage of delivered emails whose links or buttons have been interacted with by the recipient.

How are open rates measured?

In order to track open rates, we add an one-pixel image to the email itself. This is known as a "web beacon" or "tracking image".  Every time a subscriber’s email program loads that image, it contacts our email marketing software, at which point the email opening is logged.

How are click rates measured?

Any time a subscriber opens an email campaign and clicks on a link or button, it counts as a  'click through'. Click rates help gauge how effective of your email campaign is. Click-throughs indicate that the recipient is engaged with the content and wants to take the next step. So, when the click rates start to drop, it is time to check and revamp the content.

How do you measure conversion rates?

Conversion rates are the ultimate measure of your marketing campaign's efficacy. It is a metric of the number of subscribers or potential leads that you have been able to convince to take an action. For example, when you send out a survey form the conversion rate represents how many people actually complete the whole survey. 

How can opens, clicks, and conversions remain uncounted? 

There are few scenarios where some metrics may be missed :

• Plain-text emails
  

  It's impossible to track open rates when a campaign has been sent in plain text format. Because of this, we advise that you send out HTML-based emails so that we can collect metrics on your campaign.
  

• Image-only emails
  

  Most mailbox providers (Gmail, Outlook, etc) do not display images in emails by default. The email recipients are expected to actively click on "display images" to view the content.
  

  So, when you send an email with image-only message and if it's not displayed by default, your recipients will view only a blank email. This will not be counted as an email open and only when the recipient clicks "display image", it'll be considered as opened.
  

  To avoid this, Zoho Marketing Automation recommends you to avoid image-only emails and use text along with your images.
  

How to improve your open, click, and conversion rates:

• Write a great subject line that prompts users to open your message.
  
• Make sure your emails are HTML-based, not plaintext.
  
• Make it easy and convenient for recipients to see your call-to-action buttons.
  
• Use a sender address that the receiver can easily identify as genuine.
  
• Ensure that each link and button works properly.
  
• Ask subscribers to add your sender address to their contact list. This will ensure that your emails reach their inboxes every time.
  
• Schedule your emails so that you can capture the attention of your subscribers when they are most likely to be checking their mails. Consider their geographic location to decide when you should send your emails.
  
• Targeted marketing based on your subscribers' interests is one of the best strategies to increase your open and click rates.