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CTOR vs Open Rate: Which Metric is More Important for Email Campaigns?

Discover which email marketing metric is more important for your campaign's success. Learn about CTOR and open rates and how to optimize them for better results.

Marketing emails are designed to be opened and engaged with, not opened and ignored. The purpose of designing interesting, unique content is to entice a relevant audience to engage with your business—if the emails are never even opened, this can seem like a waste of time. With several other businesses also in the same boat, it can be difficult to understand how to get noticed, elevate your email campaigns to the next level and increase engagement.

In this modern age where we are inundated with email marketing daily, getting noticed is a challenge.

Although there are general statistics that can help us discern what type of approach to take, these generalizations can be unhelpful, especially as every industry is so contrasting and there is a vast difference in consumer responses per industry category.

Therefore, one of the best ways to learn how to create an email marketing campaign that intrigues your audience and makes an impact is by analyzing your metrics. The importance of your own metrics is key in learning which design, approach and strategy is best for your business and marketing.

Email marketing campaigns can show you a lot about your customers when done right. This advertising method provides you insight into the type of content they respond best to, therefore helping you figure out an email design that works well with your audience.

Unlike other methods in which you can only understand a customer's response through direct feedback, you can analyze data gathered from the emails themselves.

There are several email marketing metrics that could be considered here. In this article, we will focus on click-to-open rates and open rates, but it is worth highlighting that the click-through rate is another relevant metric.

The click-through rate provides important information by focusing on the general amount of clicks each email receives regarding the entire list of people you sent it to. The click-to-open rate is slightly different, as this is a metric considering only the people who opened the email.

Therefore, these two metrics are arguably slightly more important in evaluating the relevancy and interest of your campaign. Having said this, both metrics also have their downsides in terms of useful information.

Understanding CTOR

The click-to-open rate, or the 'CTOR' as we often refer to it, is the number of people who have opened an email sent out from an email marketing campaign and clicked on a link. This metric can be shared as a percentage or a statistic—the higher the figure, the better.

It also does not factor in multiple clicks from the same user within one email, meaning the number of clicks on the link is arbitrary.

To calculate CTOR, divide the number of emails opened by the number of successful email clicks and multiply by 100.

Advantages of using CTOR metrics

The click-to-open rate demonstrates how effective your content was at intriguing customers enough to click a link or convert the reader to interact with the email.

Therefore, this metric can be a useful way to gauge whether you need to make your content more dynamic so that it catches the reader's attention and encourages them to take action. Knowing how responsive your email recipients are to your content is essential in helping you strategize your marketing in the long run.

Some of the content issues could be in the quality of the email body. Here, we refer to the text or visual aids used to try and engage the readers.

However, a lower CTOR could also indicate an unsuccessful link or email format. Effective emails can lead to an increase in sales, meaning you, therefore, have to spend less money on other forms of marketing, so finding the root of the problem to ensure that your emails are effective and generating conversions is essential.

Understanding open rate

Defined, the 'open rate' is the number of recipients in your email campaign that opened the email. This figure is usually shared as a percentage or a statistic.

The open rate is calculated by dividing the number of people who opened the email by the number of people it was sent to.

Advantages of using open rate metrics

The open rate metric is useful in understanding whether your subject line and email headers are engaging enough and generate enough interest to encourage the reader to open the email. The open rate metric indicates how successful your subject line and headers are in piquing your recipient's interest and getting them to open the email physically.

CTOR vs open rate: pros and cons

Both of these metrics provide useful insight into the success of your email marketing, and time should be spent looking at both. CTOR provides a deeper level of understanding concerning the content itself, while open rates give an insight into how immediately enticing the subject appears to the relevant recipient.

Open rate

Some of the pros of looking at the email open rate include:

  • Insight into the overall reach of the email campaign
  • Indicates the effectiveness of the email's subject line and preheader
  • Whether the correct audience is receiving your emails
  • It can be used to determine the best time to send emails

As mentioned previously, a low open rate may indicate an ineffective email subject line or preheader. However, it can additionally provide insight into the best time of day to send an email and when people are most likely to look through their emails. Consider using some of our techniques to discover which time is best for you to email your customers.

It can also give you a good idea of where your emails end up. It could be that if the open rate is low, then the emails end up in a spam outbox as opposed to the preferable inbox that email users look through daily. Likewise, a high open rate indicates that your emails are reaching your ideal target audience, with the recipients wanting to engage with the content.

However, there are also some areas that the open rate metric does not cover. These include:

  • Clear indication of subscriber engagement with the email's content
  • May be influenced by factors such as image-blocking and preview text

Unfortunately, the open rate metric does not give any insight into the value of the email content itself. Instead, the open rate shows us how enticing the email is to open and does not provide any information on how interesting the recipient finds the actual content inside. External factors such as image blocking and preview text may also prevent the email from being opened.

How to improve your open rate

Improving your open email rate is crucial for the success of your email marketing campaigns. While several factors can influence open rates, you can also implement various strategies to increase them.

Prioritize email subscribers

If the customer has not opted in or subscribed to your email campaigns, there is a low chance that they will open it.

Rather than wasting time sending unsolicited email marketing to potentially unconvertable customers, prioritize the pre-existing subscribers who are already interested in your brand and ready to engage with your content.

Build a strong preheader and subject line

Grab the attention of your readers with a simple, informative subject line. But how can you create an impactful subject line that generates curiosity?

Ensure you highlight any offers or communicate deadlines or urgency in the subject line to heighten your chance of readers opening it. Personalizing your subject line by using automation techniques could also help with this.

Reduce the frequency and keep your emails meaningful

Although it can be tempting to inundate your subscribers with every slight update, be specific about the purpose of your email. Of course, email frequency is relative to each type of campaign, so while a large amount of updates is necessary in some circumstances and not in others, keep in mind that an influx of emails may make the reader more likely to ignore your brand when they see it in the inbox.

CTOR=Unique Clicks/Email Opens x100

Click to open rate

The click-to-open rate is an interesting metric to look at because you can gain an understanding of how your recipients respond to your content.

Some interesting, important information you can learn from the click-to-open rate includes:

  • Reflects the engagement level of subscribers with the content
  • It can be used to measure the effectiveness of the email's call-to-action
  • Provides insights into the overall effectiveness of the email campaign
  • More reliable than open rate for comparing the performance of different campaigns

The CTOR is one of the metrics that will be really useful to you when experimenting with your content. If you are trying to find which type of marketing works best within your brand or business, you may be using a variety of marketing campaigns with different styles to find your feet. In doing this or using A/B testing, you can use the click-to-open rates to decipher which style your audience responds to best.

The CTOR metric can also help you evaluate your email's effectiveness in getting the user to take action. Integrating call-to-action terms such as "click here" or "follow the link below" can help directly engage your subscribers and direct them to a page or attachment you want them to see.

Like the open rate metric, the CTOR has some areas that may limit how useful this metric is. These include:

  • Factors such as the placement and number of links in the email
  • It may not be as helpful for campaigns that do not have a clear call-to-action

Other factors could influence a low CTOR score, such as how clear the link is to the reader.

Rather than demonstrating how captivating the content is, this factor disrupts any insight into it because if the links are hidden or not obvious, some readers may not know to click on them. Likewise, if a few links are in the email, the metric will be thrown off as the CTOR only factors one click per user per email.

Not all email marketing campaigns need the recipient to take action or click on any links. Instead, it might just be an informative email that you want your subscribers to see. In this case, the CTOR metric is not relevant at all, as there is no way to measure how engaging your subscribers found the content, apart from direct feedback, for example, via a survey or questionnaire.

How to improve your CTOR

A high CTOR indicates that your email content is engaging and compelling enough to motivate your subscribers to take action. However, achieving a high CTOR requires more than just well-written content.

Implement the following strategies to improve your CTOR and increase the chances of converting your email subscribers into customers.

Be smart about each section

Compartmentalizing your content into small sections reduces the information you are giving the recipient into bite size chunks. Carefully consider the information or images you use, keeping texts short to improve readability. Place the more important sections of the content higher up in the email so that the reader immediately notices it.

Create dynamic content using visual aids

Although the well-thought-out, concise text is important, elevate your content by using images, gifs and video to create email marketing that is stimulating, eye-catching and unique to intrigue and captivate the recipient.

Improve your open rate

If your open rate is low then the CTOR will be less useful. Consider working on your open rate metric before focusing on your click-to-open rate.

Engaging links with thought-out placement

Ensure that you are directing your readers to engage with an obvious link by clearly highlighting the link with clear instructions such as "click the link below." Be clever about placing these links so they are clear and easy to see.

Factors influencing both CTOR and open rate

It is clear that both metrics provide key insight into the effectiveness of your email marketing campaigns and should, therefore, be considered when coming up with your marketing strategy. Below find a summary of all the topics that influence them.

The subject line and preheader

These are the first things a subscriber sees and can significantly impact whether or not they open the email. As explained above, these factors directly affect the open rate, but without a catchy subject line or preheader, the click-to-open rate will not be as insightful.

The more people that open the email, the more insight you get into how interesting they have found the content, influencing both click to open rates and open rates.

Email content

The content's quality, relevance, and placement can influence whether or not a subscriber engages with the email. It is useful to personalize emails so that the recipients feel they are being understood and directly spoken to.


A clear and compelling call-to-action can increase the likelihood of a subscriber clicking on a link in the email. Outlining if an offer is only available for a "limited time" or putting an expiry date on the offer can help boost these CTA terms and spur your reader to engage with the content.

Sender reputation

The reputation of the sender's domain and IP address can affect email deliverability and impact the open rate. If you want your marketing emails to be sent to the inbox and not the spam folder, then having a good sender reputation and including limited HTML coding will help the open rate and create a more insightful click-to-open rate.

List quality

A high-quality list of engaged subscribers can result in a higher open rate and click-to-open rate. Again, prioritize your subscriber list and send your emails to people who want to hear from you or read about any updates.

Choosing the right metric for your email campaigns

No single metric should be used to determine an overall consensus for your campaigns. Instead, consider several metrics when looking at the success of a campaign, as this can help you to discover any issues or areas you can improve.

For instance, high open rates but low CTOR means that perhaps the content inside of the email needs some work. Conversely, if there is high CTOR but low open rates, it might mean that you need to work on making your subject lines and preheaders more engaging.

Learn more about creating successful email marketing campaigns with Mailchimp, your one-stop shop for all the tips and tricks on getting your business to thrive.

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