Email Click-to-Open Rate (CTOR)

Discover how Click-to-Open Rate (CTOR) helps businesses measure the effectiveness of their email content by comparing clicks to opens. Learn how to track, analyze, and optimize this KPI to boost email engagement and campaign performance.

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KPI Details for Click-to-Open Rate

Category	Marketing
Type	Leading Indicator
Calculation	CTOR (%) = (Unique Clicks / Unique Opens) × 100
Measure	Tracks how compelling your email content is to those who open it, helping marketers understand content relevance, CTA strength, and overall engagement.
Data Sources:	HubSpot, Mailchimp, Klaviyo, ActiveCampaign, Campaign Monitor, Constant Contact, Salesforce Marketing Cloud.
Frequency	Tracked per campaign or weekly/monthly to identify trends and optimize future emails.

Example target

Increase average CTOR to 18% in Q3 by improving email copy, A/B testing CTAs, and optimizing for mobile engagement.

Example Reports Use Case

An Email Marketing Manager uses CTOR to evaluate content effectiveness in email campaigns. If CTOR is low despite high open rates, they may adjust layout, CTA placement, or link relevancy.

KPI Example

Best Practices for Email Click-to-Open Rate (CTOR)

Write Clear, Actionable CTAs

Ensure CTAs are visible, compelling, and aligned with the content message.
Use Engaging Visuals and Layouts

Design mobile-optimized, scannable emails that guide users toward the click.
Segment Your Audience

Send tailored content based on user interests and behaviors to boost relevance.
A/B Test Subject Lines & Content

Experiment with messaging, format, and tone to find what resonates best with each segment.

What Is Email Click-to-Open Rate (CTOR)?

Click-to-open rate or CTOR is a simple but sharp way to see if your email actually worked after someone opened it. Here’s the plain version: It tells you what percentage of people who opened your email ended up clicking on something inside it. Not just anyone who got it. Only the people who looked at it.

Let’s say you send out an email to 100 people. Thirty of them open it. Of those thirty, six click a link. That means your CTOR is 20%. You take the number of unique clicks, divide it by the number of unique opens, then multiply by 100.

Now, why does that matter?

Because opens alone don’t tell the full story. People might open an email out of curiosity, habit, or by accident. But a click? That’s intent. That means the content caught their attention. Maybe it was the way your product was framed. Maybe it was the way the call to-action stood out. Whatever it was, something worked.

CTOR helps you spot those kinds of gaps. It’s not about getting more eyes on your email it’s about what happens after those eyes land. A decent open rate tells you your subject line worked. A strong CTOR tells you your email worked.

So when you’re reviewing your campaign, don’t just ask, “Did they open it?” Ask, “Did they care enough to click?” CTOR gives you that answer.

"I remember launching a promo email for a client’s software tool. The open rate was solid—around 40%. Felt good. But the CTOR? Just 5%. We dug into it and found the email body was vague, and the CTA looked like an afterthought. Once we rewrote it with clearer copy and a button that didn’t look like a broken breadcrumb, CTOR jumped to 18% the next send. Same list. Better focus."

Alexander B. Pavlinek

Growth Marketer

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