CTR vs. CTOR: Understanding click-through rate and click-to-open rate

Clicks are the currency of email marketing, but not all click metrics tell the same story. Marketers often confuse click-through rate (CTR) and click-to-open rate (CTOR) simply because both involve the term “clicks”. However, they measure different stages of engagement. Misinterpreting them can lead to wasted effort, optimizing the wrong element, or drawing incorrect conclusions about content quality.

In this article, we’ll define both metrics, walk through simple formulas with examples, and explain when each one matters, especially in the context of transactional emails.

What is the click-through rate?

CTR measures the percentage of recipients who clicked on at least one link in your email. It shows how many people took action after receiving your message.

It answers the question: Out of everyone who received this email, how many clicked?

Purpose: Calculating the click-through rate is to understand the overall effectiveness and to measure engagement of a campaign or transactional email. With this, you can improve your performance in these aspects of the email:

• Deliverability.

• Subject line effectiveness.

• Preheader impact.

• Email design.

• Copy clarity.

• CTA/link placement.

• Media quality.

• Brand interest from campaigns.

How do you calculate CTR?

Formula:

Example: A bank sends a transactional email, such as a payment confirmation or an account statement, to 10,000 customers and 1,000 customers click on the “View Statement” or “Download Receipt” link.

So:

• Emails delivered: 10,000

• Number of unique clicks: 1,000 customers

CTR = (1,000 ÷ 10,000) × 100 = 10%

This means 10% of recipients took action after receiving the transactional email.

What is the click-to-open rate?

CTOR measures the percentage of people who clicked after opening your email. It isolates the performance of your email content and call-to-action.

It answers the question: Of the people who opened this email, how many clicked?

Purpose: CTOR focuses only on the clicks that happened after the email was opened. It isolates the performance of your:

• Email content.

• CTA call-to-action.

• Email layout.

Note: Remember, CTOR depends on open tracking accuracy. It’s important to note that privacy features such as Apple’s Mail Privacy Protection (MPP) can inflate open rates, which may slightly distort CTOR values. Because of this, CTOR should be used alongside other engagement metrics, not in isolation.

How is CTOR calculated?

Formula:

Example: Let’s calculate CTOR using the same bank example.

Suppose a bank sends a transactional email, such as a payment confirmation or account statement, to 10,000 customers. Out of those, 4,500 customers open the email and 1,000 customers click on the “View Statement” or “Download Receipt” link.

So:

• Emails delivered: 10,000 emails were delivered

• Emails opened: 4,500 customers

• Unique clicks: 1,000 customers

CTOR = (1,000 ÷ 4,500) × 100 = 22.22%

This means 22.22% of the customers who opened the email clicked on the link. 

CTR vs. CTOR: Key differences

When should you track CTR vs. CTOR?

Both metrics matter for emails, but they’re used in different contexts.

1. Promotional campaigns

The purpose of sending promotional campaigns is to drive conversions and revenue. For promotional campaigns you can use both CTR and CTOR because:

• CTR helps evaluate overall ROI.

• CTOR helps optimize content and CTA placement.

2. Newsletters

Newsletters are built to educate, inform, and maintain engagement. In this case, calculating CTOR is more useful.

Because newsletters often rely on content blocks, design, and navigational CTAs, measuring CTOR reveals whether readers found the email engaging enough to explore further.

3. Transactional emails

Transactional emails are time-sensitive emails triggered based on user actions. So in this case, calculating CTR is more important for emails like password resets, order confirmation, shipping alerts, and invoices.

The goal is action completion. CTOR is less meaningful because open intent is already high for transactional emails.

4. Lifecycle/drip campaigns

Drip campaigns nurture users toward the next stage in the journey. So calculating CTOR is valuable for optimizing email flows.

CTOR clearly shows whether the email content is successfully moving engaged users toward the next step.

5. Re-engagement campaigns

The main goal of re-engagement campaigns is to reactivate inactive or dormant users. So the primary focus should be on CTR.

Because open rates can be unreliable due to privacy tracking, clicks are stronger indicators of true engagement.

Best practices to improve CTR rates

CTR is calculated to learn how many people clicked out of the total number of emails delivered. So improving CTR means improving overall engagement across your entire audience, not just those who opened your email. Here’s how you can do that.

1. Set the right expectation in the subject line

Your subject line should clearly reflect what’s inside the email. Misalignment instantly kills clicks, especially in promotional campaigns. When expectations and content align, readers are far more likely to click the email

For example:

• If the subject promises “Download your invoice,” the email should make that action immediately visible and easy.

• If it says “30% off ends tonight,” the offer should be front and center, with no scrolling, searching, or confusion required.

2. Make your CTA obvious

Clarity beats creativity. Transactional emails especially should remove thinking. When someone opens a password reset or order confirmation email, they want one clear next step.

Instead of using vague CTAs like “Explore now” or “Click here”, try using straightforward CTAs like:

• “Download invoice”

• “Track order”

• “Upgrade plan”

• “Claim your 30% discount”

3. Reduce friction

A beautifully written email won’t help if your landing page takes 10 seconds to load. CTR isn’t just about email design, it’s also about the post-click experience.

Ask yourself these questions:

• Is the link broken?

• Does it open slowly?

• Does it redirect too many times?

• Is it mobile-friendly?

Based on the answers, optimize your email to improve your click-through rates.

4. Segment based on intent

Relevance drives more clicks. Sending the same email to everyone rarely delivers results. So first, understand your recipients’ intent, segment your audience accordingly, and tailor your content to match their needs. The more relevant your message, the higher your click-through rate will be.

For example:

• First-time buyers → send onboarding emails.

• Active users → send feature updates.

• Inactive users → send re-engagement offers.

• Premium users → send loyalty benefits.

5. Use urgency only when it’s real

Urgency works better only for those emails that are truly time-sensitive. Make sure to create urgency for the emails that are sent after a user performs an action. Remember, fake urgency reduces trust, especially in transactional emails.

For example:

• “Password reset link expires in 10 minutes”.

• “Offer ends in 3 hours”.

6. Optimize for mobile first

Most users check emails on their phones. If your email isn’t mobile-optimized, your CTR will silently drop. Make sure to check these elements before sending your emails:

• Buttons should be large enough to tap comfortably with a thumb.

• Links should have enough spacing to prevent accidental clicks.

• Text should be clear and readable without requiring users to zoom in.

• Images should load quickly and display properly across devices.

Best practices to improve CTOR rates

CTOR answers a different question: Among the people who opened your email, how many clicked and engaged with your email? This isn’t about getting opens, it’s about converting attention into action. Here’s how to improve CTOR.

1. Convey the context within 5 seconds

When someone opens your email, you only have a few seconds before they decide to close it. Make sure to keep your design clear and that the information you want to conveyed is positioned above the fold. No one should have to figure out why they received the email.

For promotional emails, highlight the offer immediately. For transactional emails, highlight the action to be done immediately.

2. Keep it focused on one primary action

Multiple CTAs can be harmful for your email. It will create decision fatigue among readers. So always have one primary email CTA. 

If the goal is:

• Reset password → have one clear button.

• Confirm subscription → have one clear action.

• Grab sale offer → have one primary CTA.

Secondary links (social icons, help center, customer support) can exist but they shouldn’t compete visually. Remember, CTOR improves only when the email feels intentional and not cluttered.

3. Use the visual hierarchy wisely

Most email users tend to scan emails rather than read them. The design should guide their eyes naturally toward the action.

Your CTA should:

• Stand out in color.

• Include enough white space.

• Be repeated if the email is long .

4. Personalize beyond just the name

The more context you add, the more compelling the click becomes. This works beautifully for both lifecycle transactional emails and promotional campaigns. “Hi Sarah” is basic. Instead:

• Recommend products based on browsing behavior.

• Show the subscription renewal date.

• Mention the plan name.

• Show the reward points balance.

5. Remove distractions

Sometimes improving CTOR means removing elements, not just adding them. Only clarity converts. A clean, focused email makes it easier for readers to understand what action to take.

Ask these questions after designing your email template:

• Is there too much text?

• Are there too many images?

• Are we trying to say too many things?

6. Build trust visually

When users trust the sender, they’re more likely to click the links inside an email. Because phishing and scams have made recipients cautious about clicking links, it’s important to build and maintain credibility in every email you send.

To strengthen trust:

• Use your brand logo clearly and consistently.

• Maintain consistent brand colors and design.

• Avoid spammy formatting, excessive capitalization, or misleading language.

• Keep the tone clear, professional, and authentic.

Wrapping up

CTR and CTOR aren’t competing metrics. They answer different questions about your email performance.

On one side, CTR shows how effectively your email drives action from the entire audience. On the other side, CTOR reveals how compelling your content and CTA are once the email is opened. Looking at only one metric can give you an incomplete picture.The key is to use them together to drive engagement.

If CTR is low, investigate deliverability, targeting, or subject lines. If CTOR is low, refine your messaging, design, and call-to-action. When both are strong, you know your email is working end to end.