When’s the Best Time to Send Your Emails? Smart Send Time Has the Answer.

Send Time Optimization

One thing all email marketers want to know is, “When is the best time to send my emails?”

A marketing automation feature like Klaviyo’s Smart Send Time answers that question for you. 

What is send time optimization? 

Send time optimization automates what used to be the slow, difficult process of identifying the best time to send your emails.

Figuring this out on your own takes a lot of testing, reporting, iterating, and most importantly, time.

Many of the popular email and sms marketing platforms like Klaviyo, should have a Smart Send Time feature that automates this process so all you need to do is click send. 

Taking the example of Klaviyo’s Smart Send Time, the feature uses custom-developed smart optimization technique to learn the behaviors of customer email recipients to tell them exactly when to send future messages to maximize open rates.

The feature will also continually adapt to any changes in customers’ behavior, so the best time to send emails will automatically change as the customers’ behavior changes. 

How does a feature like Klaviyo’s Smart Send Time work? 

To get a full view of how this feature works, we’re going to use Smart Send Time to find the best send time for a fictional ecommerce business called the Corner Three. 

Corner Three sells basketball gear and accessories. The brand wants to let subscribers know about a new style of basketball socks through a promotional email.

Normally, Corner Three sends its promotional emails at 10:00 a.m. and uses the schedule by recipient time zone feature so each person receives the email at 10:00 a.m. local time. But this time, Corner Three sees the Smart Send Time option and wonders, “Is 10:00 a.m. truly the best time for us to send our emails?”


send-time-optimization feature in Klaviyo


Corner Three selects Smart Send Time and sees its first campaign email will send over a 24-hour period.

Why? To get an accurate reading, a automation platform like Klaviyo needs to learn about how people in Corner Three’s list interact with emails at all different times of the day.

To do this, the first campaign sends at regular intervals over a 24-hour time period to check open rates across the entire day.

There’s a tradeoff here—some emails will be sent at suboptimal times with lower open rates (like 2:00 a.m.), but Corner Three will know its optimal send time for all future emails.


send-time-optimization-report in Klaviyo


Corner Three’s campaign goes out to its main newsletter list. A couple of days later, after all the open and click information has been collected, Klaviyo automatically analyzes the data.

The next time Corner Three sends its standard weekly newsletter to the same list, the brand will have the option to send it at the optimal time—6:00 p.m.

Based on the learnings from the initial 24-hour send, Corner Three now has a send time it can use to maximize its email engagement going forward.


send-time-optimization-ready to send option in Klaviyo


Once Klaviyo finds the best send time, the learning doesn’t stop learning there. Each subsequent time Corner Three sends to this list using Smart Send Time, the model will test the result and ensure the send time is still optimal.

To do this, the platform sends the email within a four-hour window centered on the optimal send time.

In this case, since Corner Three’s optimal send time is at 6:00 p.m., the platform will send some emails at 4:00 p.m. and some at 8:00 p.m. By continually collecting engagement data at different times, algorithms will detect any changes to the optimal send time and shift the time automatically.

By using the Klaviyo feature, Smart Send Time to send just a couple of emails, Corner Three learned the best time of day to maximize its email engagement.

Over the course of the next month, Corner Three started sending its campaign emails at the optimal send time and saw a 12 percent increase in open rates! 

Throughout our testing with customers, brands that sent their emails using the newly optimized send time feature saw their open rates increase by 10 percent on average.

By allowing a platform like Klaviyo to automate the data science part of the process, you get a statistically optimized send time without spending hours of time figuring it out yourself.  

Try Klaviyo free to start using Smart Send Time today or boost your email engagement and own your growth. 


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