Identify the Best Time to Send Emails (Marketing Platform) | Klaviyo Blog
2026-03-10 14:54 Diff
https://www.klaviyo.com/blog/smart-send-time-audiences

There are numerous benefits to email marketing and as brands scale their email program they can strategically increase their email open rates, especially if they set-up email automations that engage and re-engage their audiences.

When you’ve got your email campaign ready to be sent (you’ve perfected the content and copy, plus matched it to your segmented audience), the final challenge is understanding the best time to send this email to get the most people to open it?

This is one of the biggest challenges email marketers have, especially as global and national time zones have to be taken into consideration.

So how do marketers best manage their email marketing channel to ensure the email automations and flows they set up for their campaigns are sent at a time that maximizes email open rates?

Email marketing automation platforms and smart send time.

There are a plethora of top email marketing automation platforms in the digital marketing space.

However, it can be hard to understand all the features without first using them, plus not all offer a ‘best send time’ feature in their tool.

One platform that does offer such a feature is Klaviyo. It has a “Smart Send Time” feature which solves this challenge.

Other marketing automation platforms may have similar features so here we will focus on helping you understand how to use smart send time.

Smart Send Time uses a custom-developed optimization technique to learn the behaviors of your email recipients and tell you exactly when to send messages to maximize your open rates.

Smart Send Time also has options to identify a Smart Send Time for multiple unique audiences.

Test messages and send at the right time

The way Smart Send Time works is that you send an exploratory message to at least 12,000 recipients across a 24-hour window.

  1. This “focused sends” in a four-hour window centers on the optimal send time.
  2. Once an optimal send time is established, you can use it to send any future email.

Then, Klaviyo automatically uses a four-hour window around your optimal send time to keep collecting engagement data.

For example, if your optimal time is 12 PM, then Klaviyo will send some emails between 10 AM -12 PM and some between 12-2 PM to continue to learn from customer engagement behavior. This way, if customers start opening earlier or later, Klaviyo can automatically adjust the sending time.

Smart Send Time is flexible as you can:

  1. Run multiple Smart Send Time tests, which means sending multiple exploratory sends to different audiences.
  2. Keep sending exploratory messages over a 24-hour span. This allows Smart Send Time to continue gathering open rate data while sending outside your Focused Send window.
  3. Send directly at your Optimal Send Time without the four-hour window. This is an easy way to send an email at your best time, in one click. This option lets you send a campaign to 100 percent of your recipients at your optimal send time and won’t gather more engagement data.

Multiple Smart Send Times for each account

You can have more than one Smart Send Time in your account!

What does this mean? As long as you have enough recipients to run an exploratory send (12,000+), you can find out what your optimal sending times are for different segments of customers or even days of the week.

For example, maybe the best time to email your newsletter list is 10 AM, but your VIPs are more likely to engage at 7 PM.

Maybe Tuesday you should send your campaigns to your main list at 11 AM, but if you send it on a Thursday, you should send it at 6 PM.

  1. Re-test your original Smart Send Time test from the Exploratory phase without losing the original test’s learnings.
  2. Measure whether there’s a difference in ideal send time (by way of highest open rate percentage) for recipients who click on your messages versus recipients who open your emails but don’t click.
  3. Test optimal send times by season and/or by seasonal product line.
  4. Test optimal send times by campaign type. For instance, test whether your newsletter campaigns have a different optimal send time than your sale campaigns.

Results that are easier to understand

After you’ve sent one or more Smart Send Time campaigns or tests, you can view your results on the Smart Send Time Report page. This page is accessible via the “Options” dropdown on the Campaigns tab.

For any Smart Send Time test, you can view all of the underlying data. You can see:

  1. Open rates by hour for exploratory sends – shows you how Klaviyo selected your Smart Send Time
  2. Open rate lift – tells you the increase in open rate when sending at your original Smart Send Time compared to the open rate data of your exploratory sends
  3. The Activity Timeline – shows a timeline view of all campaigns sent in a given experiment. It includes when a campaign was scheduled, canceled, and started sending as well as its send type (exploratory, focused, optimal, etc), when the campaign’s data was analyzed (attributed), and whenever a smart send time changes for the test

Additionally, if you’ve run multiple Smart Send Time tests you can view and compare the data for each test. If those tests targeted the same segment of customer, you can look at the underlying data and compare the hour open rates to more fully understand how your Smart Send Time was formed.

Looking at your results may inspire you to test something new—a new day of the week, a new audience subgroup, or a new type of campaign.

If you do get inspired, you can start a new test from the reporting page. Simply click “Create New Test” to open up a modal where you can name your new test and add any notes to remind yourself about what the test is and why you tested it for future reference.

Learning the best time to send your emails has never been easier. These updates to Smart Send Time allow you to run tests on eligible groups of subscribers and pinpoint the right time of day to send their next campaign.

If you have a group of at least 12,000 recipients, start a new Smart Send Time test today!