Click-to-open rate (CTO) is a valuable but sometimes misunderstood email metric. It shows how many people who opened your email clicked on something inside it. Usually a link, call to action, or image. In short, it measures how engaging your email content was once someone took that first step and opened it.
CTO is often confused with CTR (click-through rate), which looks similar but tells a slightly different story. Click-through rate is the number of people who clicked your email link divided by the number of emails you sent. However, the CTO focuses on the people who opened it, not everyone you sent it to. That makes it more about content performance: was your email clear, convincing, and relevant, rather than delivery or subject line success?
Marketers lean on the CTO to understand whether their email copy and design are doing the job. If your open rate is high but CTO is low, your headline worked but the email body didn’t follow through. The message may have been too long. Or confusing. Or the call to action wasn’t clear. Conversely, if your open rate is low but your CTO is strong, it might be time to work on subject lines and sender details.
Does an all-caps subject line grab attention? Where should you put your CTA for max impact? See what Spotler tested on their own audience.
Every marketer has a segment they avoid looking at too closely: the cold list.
With the right pre and post Valentine’s campaigns, you can lift revenue, strengthen your data and turn one off shoppers into loyal customers. Join us to find out how!
Get more out of the events you’re already running. Combine efficiency with a professional experience for your attendees and stop leads slipping through the cracks and follow up with ease.
One of the biggest emerging opportunities is citation analysis and citation building for AI platforms. Find out how you can get AI to cite your brand via GEO.
Galentine’s Day has grown from a small cultural moment into one of February’s most commercially interesting trends.
Heart emojis and pink colour palettes are less likely to move your business customers. But there are other ways to make use of Valentine’s Day.
Buyers want the personal touch, but they don’t want you too close. How do you get the balance right this Valentines Day?
How do you turn your Valentine’s shoppers from spring fling to long-term relationship?
Inboxes are more competitive than ever; it is estimated that 376.4 billion emails were sent every day in 2025.