How to choose the best time to send email marketing messages? Research-backed engagement stats

Profile photo of author Annie McGreevy
Annie McGreevy
23min read
Email marketing
February 9, 2023
Image shows a man listening.

You’ve grown your email list to thousands of subscribers.

Your marketing team has iterated on an email campaign design with the perfect email subject line, preview text, and headline, along with a perfect, can’t-turn-away-from-it CTA.

The whole process has taken weeks and you’re ready to hit send, excited to see the results.

Why? Because the success of an email campaign, and your larger email marketing program, translates to more revenue that’s owned entirely by your business and customer connections that aren’t reliant on middle-man algorithms to foster.

And in today’s unpredictable, and frankly uncertain, economic climate every teeny tiny decision matters. The more profit you can squeeze out of low-cost programs like email marketing, the more resilient your business becomes when faced with these squirrely headwinds.

So now you’ve got 2—small, but important—decisions to make:

  1. What time will the email go out?
  2. And on what day?

These questions seem straightforward enough, and the internet is filled with a number of resources about the optimal time to send an email.

But the truth is there’s no simple answer. There are a variety of factors to consider, including:

  • What type of email campaign you’re sending: Yep, the best time to send out your weekly email newsletter is different than the best time to send out your product launch.
  • Who you’re sending it to: Is the email going to your VIP subscribers, customers you’re trying to win back, or a demographic in between?
  • What’s happening where your email subscribers are located
  • What kind of products or services you sell
  • How often you normally send emails or marketing text messages

Whether you’re manually optimizing your send times or using data and machine learning to make these decisions, you’ll want to send your emails at time slots when your target audience is most likely to see them and engage with them.

And because there are so many factors to consider, Klaviyo’s Business Intelligence team collected and analyzed data and metrics from thousands of Klaviyo customers to try and find patterns brands like yours can rely on and simplify these answers. We also chatted with email marketing experts to put together this guide on how to determine your email send times.

Keep reading to learn:

Customer engagement is on the line: why timing matters in email marketing

Most inboxes have one thing in common: they’re full.

For over a decade, the average person has gotten upwards of 100 emails a day. Despite more channels to communicate through, that number is bound to keep rising.

Unless your customers are managing multiple email addresses, your marketing emails are in the same view as messages from their family, work, friends, and potential spam senders.

Why should your subscribers open your email?

Of course, there are several factors to help you achieve the engagement KPIs you’re aiming for: subject lines, preview text, and making sure your list is clean, to name a few.

But, the timing of your emails is one of the most important ways your messages can stand out.

Absolute vs. relative timing

Carlos Barrero, strategic partner manager at Klaviyo, says timing is among the three most important variables marketers can control in their email marketing strategies.

Email send times can be absolute—for example, sent at 9 a.m. on Thursday. But they can also be relative to a customer’s journey. For example, emails sent after a customer makes their first purchase, or on their subscription anniversary, are relative versus absolute in terms of email timing.

“Messages sent at relative times tend to be more timely, feel more personalized, and ultimately perform better,” Barrero says.

Messages sent at relative times tend to be more timely, feel more personalized, and ultimately perform better.
Carlos Barrero, strategic partner manager

Good news: emails sent using relative timing are easy to automate in Klaviyo.

Val Geisler, customer advocacy lead at Klaviyo, spent years as a conversion strategist for B2C startups. She emphasizes that knowing when your customers like to receive messages is only one piece of the B2C marketing puzzle.

“The timing of your emails is also relative to your product,” she says. “If you sell a breakfast item, message your customers in the morning while breakfast is on their mind. If you make products for busy professionals, it may help to hit their inbox on Sunday afternoons while they’re prepping for the week. Getting the right send time down for your product will increase engagement from your customer base.”

New research highlights email engagement throughout the year

Before we get into the nitty-gritty of days and times, let’s think bigger.

What’s happening throughout the year? As you plan your annual marketing calendar, it can be helpful to understand big-picture trends and takeaways that affect how folks engage with your emails in ways that are more outside of your control.

Click rates peak in November and January

Average click rates hover between 0.80% and 0.88% for most of the year, rising to 0.91% in November and January.

Of course, November’s uptick comes from BFCM. The rise in January is likely due to post-holiday promotions.

Image shows a chart indicating click rates by month
Image source: Klaviyo

These peaks correspond to BFCM and New Year’s sales. It’s worth putting more muscle into your marketing strategies during these seasons, given that engagement rates are so much higher.

Open rates rise through summer and fall

Average email open rates throughout the year remained steady, close to 30%, rising through the summer and fall. They peaked in November, close to 35%, and started to dip down again in December.

Open rates rising in the late summer and fall may include back-to-school shopping, Halloween, and, of course, BFCM.

Image shows a chart indicating open rates according to months
Image source: Klaviyo

Klaviyo-attributed value peaks in November and April

Brands using Klaviyo as their ESP earned about $0.05 per received email in 2022, with the exception of November, when the median was $0.07.

Klaviyo-attributed value (KAV) took a dip in December, presumably because shoppers front-load a lot of their purchases ahead of the December holidays. It climbed back up to $0.05 by January.

Apart from the winter holidays, KAV rose in April as well. While we don’t have hard data on why that is, consider how the change in seasons paired with upcoming gift giving holidays could spur spending.

Folks may begin shopping in April for:

Image shows the amount of revenue generated by email service provider Klaviyo according to month
Image source: Klaviyo

What days are best to send your email marketing campaign?

Our data found that, among brands using Klaviyo as their ESP, the highest number of emails were received on Fridays. That varied during warmer months—March, June, and September saw more emails received on Thursdays, and May and August saw the most emails received on Tuesdays.

Throughout the year, the day Klaviyo brands saw the least amount of received emails was Saturday, followed closely by Sunday.

Image shows a chart indicating which days more emails get received.
Image source: Klaviyo

Don’t schedule all your campaigns for Fridays just yet, though. Barrero cautions that data like this must be carefully weighed against other considerations.

“From a certain point of view,” he says, “there’s greater likelihood of competition in the inbox in the afternoon, and on Fridays”

From a certain point of view, there’s greater likelihood of competition in the inbox in the afternoon, and on Fridays.
Carlos Barrero, strategic partner manager

Geisler sees this trend as the expression of marketing teams spending all week on a campaign and finally sending it on Friday. “Try to get slightly ahead of your messaging, so you can send earlier in the week,” she suggests.

Klaviyo’s Smart Send Time feature can tailor insights like these for your specific business.

What time of the day is best to send emails?

Klaviyo brands saw the most emails received in the afternoon, followed closely by the morning hours of the day. The time of day the least amount of emails were received was nighttime.

Image shows a chart indicating the times of day when the most emails were received, which was during the workday.
Image source: Klaviyo

It makes sense, then, to time your email sends either in the afternoon or morning, depending on the factors that matter to your target audience and overall business.

Geisler sees the cutoff between “evening” and “night” as a possible opportunity to send during a less busy time, taking into consideration, of course, when it would be too late for your particular demographic.

Setting up email send times manually? Consider these factors before you start

Marketers have plenty of reasons to set up send times manually: sometimes smaller businesses don’t have the subscriber list size needed for machine-learning features to run as intended, you may be reworking segments, or you may be frequently testing on your own.

Or, you may just be anxious about turning the reins over to an AI-powered feature, when the stakes are high to meet revenue and performance goals.

“Some brands worry that changing anything will result in less revenue,” Barrero says. “Certain marketing goals and incentives can discourage experimentation and, by extension, learning and growth.”

No matter what your reason, if you’re setting up send times for your email campaigns manually, you should be thinking about who is in your audience and how they interact with your emails.

What time does your audience usually check their email?

Are they highly engaged shoppers who are likely to mark the email and come back to it?

Are they parents who may not get a chance to sit down in front of a screen until after they’ve put their kids to bed? Entrepreneurs who get email alerts on their phones?

What about seniors who might not check their email every day?

What you know about your target audience, their lifestyle habits, and device usage (or lack thereof) can help you determine what day and time you send an email campaign to a certain demographic.

What is the action I want this segment to take?

For many marketing emails, the action you’re hoping to inspire is a visit to your brand’s product page and a subsequent purchase.

But if you have other goals—for instance, that readers of your email join your loyalty program or read your newsletter, you’ll want to think through some other questions.

Might they read your newsletter during a lunch break or on their train ride home on a workday? If so, time that send accordingly.

If joining your loyalty program requires a few steps or a little research, consider sending those emails when your demographic might have a little more bandwidth to take on the task.

What time is it where they are, and what’s happening?

Don’t forget about time zones.

If you want your email to land in your audience’s inbox at 9 a.m., make sure your ESP is set for it to arrive at 9 a.m. local time.

Image shows a screen from a Klaviyo dashboard showing how to set your email sends to the audience’s time zone.
Image source: Klaviyo

A good ESP will account for user time zones automatically, but Barrero emphasizes that “what your ESP knows about your customers’ time zone is only as good as the data you give it.”

“Make sure your data is up-to-date and that your organization follows good list hygiene practices,” he says.

Time zones aren’t the only geography-based aspect you need to take into account.

“Understanding localization is important in terms of time zones (don’t hit your cupcake enthusiasts at breakfast time, for example), but also to understand what’s happening in their part of the world at that time of day,” Geisler shares.

Localization is always relative to what you sell, who your customers are, where they are in the world, and what’s happening at the time you send.
Val Geisler, customer advocacy lead

“Things like sunrise and sunset happen at different hours depending on how far north or south you are. Surprisingly, those things matter for lots of brands and shoppers. Particularly if you sell, say, blackout curtains or melatonin,” she says.

“Localization is always relative to what you sell, who your customers are, where they are in the world, and what’s happening at the time you send,” Geisler says.

How frequently you send your customers emails

Looking at your email marketing program holistically, ask how often you send your customers emails. That’s a factor you’ll want to take into consideration when deciding which day and what time to send them other emails in the future.

Best practices for campaign frequency per month tends to land between 2-5 messages. To determine the best send time for those few, make sure you’re taking into account:

  • Everything you know about your customers
  • Everything that’s relevant to your products
  • Any context about time of day, season, where your subscribers are, etc.

If you’re sending a certain segment of your audience an email every day or close to that cadence, consider varying the times you send so that you can test open and click rates to inform future strategies.

With Klaviyo, you can turn on Smart Sending, which serves as a buffer between messages so your subscribers won’t receive too many emails from your brand in a certain amount of time.

What kind of email you’re sending

Depending on what kind of marketing email you’re sending, you’ll want to think through some questions to determine your send time.


  • How long will it take to read your newsletter?
  • Do you want folks to read it all in one sitting or is it okay to be read bit by bit, with the reader taking breaks?
  • Is there anything in the newsletter that would be better read at a certain time of day, or on a certain day?

One-time discounts

  • Urgency is key for a one-time discount, so, ask yourself: How much is enough time for subscribers to engage with the email, click through to your product pages, and make a purchase?
  • Make sure it’s not so much time that they can leave it too long, and risk forgetting about the discount entirely.
  • Consider including a countdown clock in your email so that the urgency is crystal clear to your readers.

Product launches

  • How long have your most engaged customers been anticipating a new product? Consider sending an earlier email to them, giving them access ahead of when other, less engaged segments will get it. This will help foster a feeling of exclusivity and build loyalty.
  • How many emails should you send for this product launch in total? How can you build momentum for the product launch?
  • Send out emails before the launch to get your subscribers excited.
  • Time out emails featuring customer reviews, user-generated content, and other teasers.
  • Is your subscriber base engaged enough that they won’t get overwhelmed getting an email every day (even for a short period of time)? If the answer is yes, consider timing those pre-product launch emails according to the action you want them to take.

Automated email flows and perfect timing make for a seamless customer experience

Winback, browse abandoned cart, and welcome series emails should all be timed according to the customer journey. Here’s how to think through that.

Winback flows

You should send a winback email when a customer is inactive. Most are generally considered inactive after 3-6 months, but if your purchase cycle is longer—say, if you sell coats or mattresses—you’ll need to determine how many months would constitute “inactivity”.

Browse abandonment

If you’re trying to incentivize a new subscriber to make their first purchase, but you don’t want to overwhelm them, set up a trigger that sends the browse abandonment email with a captivating subject line only after they’ve viewed the product a certain number of times.

To try to re-engage a one-time purchaser, time your browse abandonment sends based on how recently they placed an order from you.

For example, if they just bought an item from you yesterday, they most likely don’t want to receive an email that says, “Hey, did you forget something?” Instead, set up your browse abandonment automation to exclude subscribers who’ve made a purchase within the last 30 days.

If someone hasn’t made a purchase from you in months but browsed this morning, send that email within hours and consider offering them a discount or free shipping to entice them back to the product page.

Abandoned cart

The first reminder that a shopper has abandoned their cart should get sent 2-4 hours after abandonment.

If they don’t engage with that email, send another 24 hours after that.

Welcome series

Send that first welcome email immediately after someone signs up for your service. Don’t delay—they might lose interest or forget they signed up in the first place.

After that, try to leave at least 1 day between emails so subscribers don’t get overwhelmed.

You should also try to finish your welcome series within a week, if there are multiple within your automation.

Have more than 10K subscribers on your list? It’s time to lean into AI and machine learning

If you’re in the early stages of growing your list, it makes sense that you might still need to determine your send times manually. But once you’ve got around 10K profiles (or subscribers) on your list, it’s time to start checking out AI options, especially if your list is actively growing.

Barrero cautions that AI tools are only as good as the data used to power their analysis. “It behooves marketers to understand the basics of machine learning concepts and probability,” he says.

While you don’t need to have technical knowledge to build your own models, it’s important to reframe how you think about causality, Barrero says.

“Machine learning models can’t tell you what is ‘more right’ or ‘more accurate’. Instead, the aim is to try and find the ‘least wrong’ or ‘less risky’ possible outcomes in your problem scenario,” he explains.

“Thinking in terms of ‘likelihoods’ can feel scary to marketers looking for clear and easy solutions,” he says. “But it can also be freeing in realizing that there are no perfect answers in digital marketing, let alone in message timing.”

Good decisions come from understanding your unique circumstances and being informed—but not exclusively driven—by data.

Once you’re ready to dive in, the benefits of AI and machine learning are significant: specifically, users report cutting costs. But that’s not all.

Email send time confidence

All the effort that goes into creating a marketing email is wasted if your subscribers don’t open it. That’s why it’s so crucial to time them when they’re most likely to be opened.

The right AI tool will use a robust, reliable testing framework to gather the data you need to decide send times. A good one will also share those results with you in an easy-to-understand format, making your next actions clear.

For instance, let’s say you sell makeup to people mainly in their 30s and above. You’ve assessed that this audience will be more likely to engage with your marketing emails after they’ve put their kids to bed or are scrolling after dinner.

A good AI tool may report more engagement during the afternoon versus at night—offering contradictory information to what you may have previously thought.

Maybe they’re taking a break at work, or are waiting to pick their children up from an activity.

What matters is that the tool removes the guesswork. You can shift your send times from nighttime to the afternoon and track your results.

More deep, creative work for your team

Raise your hand if you love sifting through a huge pile of data and evaluating the likelihood of a single person or demographic opening an email at a certain time.

Chances are, few people on your team will miss the initial work of collecting and analyzing this kind of data.

Good news: It’s that type of work that certain machine learning algorithms can take care of for you.

With economic uncertainty looming and layoffs across tech, plenty of marketing teams are getting leaner. Artificial intelligence is one way to free your team up for other, more creative work: like strategizing and building marketing assets.

Automated A/B testing for improved engagement and increased sales

The more your customers are opening your emails, the better the chances are that they’ll click through to your product pages and make a purchase. But not every segment has the same timing preferences, and your time might not have the capabilities to run endless, manual A/B tests.

This is where the capability of your ESP is crucial.

You’ll never know the difference if you don’t test them separately, and Klaviyo makes this easy.
Carlos Barrerro, strategic partner manager

“Send time optimization can be scoped to the type of content you send or audiences you send to,” says Barrero.“That is, you can run several send time optimization experiments in Klaviyo and have different results. For example, your audience for a weekly flash sale email reminder may have a different optimal send time than a new product announcement audience around a specific product segment.”

“You’ll never know the difference if you don’t test them separately, and Klaviyo makes this easy.”

So, how can you get there?

Klaviyo’s Smart Send Time can take the manual load off of your plate

Klaviyo’s Smart Send Time feature uses your business’ data to tell you the best time to email your customers. If your list has 12k profiles or more, you can use it.

With this feature, you can:

  • Better understand your customers’ behavior around opening emails
  • Maximize your open rates
  • Maximize your clickthrough rates

Our model figures out when your customers are most likely to open your emails. And you can always see your results in your Klaviyo dashboard.

Image shows a chart from a Klaviyo dashboard indicating the time of the day when your open rates are highest.
Image source: Klaviyo

How does Smart Send Time work?

First, you create a test email that you send to your entire list. This is called an exploratory send.

Klaviyo will send that email over a 24-hour period, with customers randomly assigned different times to receive it.

After that exploratory send, Klaviyo finds a focused send time—a period of time when the highest number of people opened your email.

From there, the tool continues to make sure that’s the ideal window to send your email because a higher proportion of the folks who get it will open it at some point. If it’s not, it refines its recommendations based on customer behavior changes.

Once you’ve started using Klaviyo’s Smart Send Time feature, you’ll know the window to send your email that is likely to give you the highest open rate. You can use this to choose what time you send your campaigns.

Image shows a screen of Klaviyo’s Smart Send Time feature
Image source: Klaviyo

A smart send time for each type of email you send

If you’re already segmenting your list, you’ll want to know the optimal send times for multiple demographics.

Good news: You can find an optimal send time for each segment you send to with Klaviyo Smart Send Time.

This means you can send each segment their emails at the time that is most likely to maximize the likelihood of them being opened.

Smart Send Time vs. Smart Sending: what you need to know

Smart Send Time lets you run tests to determine the best time to send your emails.

Smart Sending, on the other hand, makes sure you don’t bombard your customers with too many emails over a short period of time.

When you’ve enabled Smart Sending, Klaviyo automatically checks to see if a customer has gotten a message from you within a certain period of time. If a profile has gotten an email from you too recently, they won’t receive the current message.

You can use Smart Sending for both email and SMS.

The default window of time for email is 16 hours, while for SMS, it’s 24 hours. If you want to change the window of time, you can do that at any point.

Find the best email send time for your customers—and ultimately your brand

Whether you’re strategizing your next campaign or planning your annual marketing calendar, make sure you’re getting the most out of your owned channels: email and SMS.

Sending emails at the time they’re most likely to be opened—and actually read—is one of the best ways to set your brand up for success. Spend some time with Klaviyo’s Smart Send Time and discover how you can make incremental strides towards your larger revenue goals.

Best email send times FAQs

What is the best day of the week to send emails to subscribers?

According to Klaviyo’s business insights, Friday and Thursday afternoons are the best weekdays for email deliverability. However, since every audience and business is unique, the real answer is that it depends. There are several variables that can influence email sending times, such as the typical workweek, the purpose of the email, etc. One way to take the guesswork out of manually optimizing email send times is to use AI technology to analyze and customize email send times based on customer behavior.

What is the best send time to increase email open rates?

This entirely depends on the type of email you are sending. Emails that are tied to the customer journey, like welcome emails or abandoned cart emails, should be scheduled based on when your customer interacts with the email trigger. For promotional emails, it is best to glean an understanding of your audience’s engagement levels as a starting point by looking at historical email open rates and testing different send times.

What is the best way to optimize email send times?

If your email list is less than 12K subscribers, manually segmenting and A/B testing email send times can help you determine when to send your emails based on higher open rates. However, if you have more than 12K subscribers, you can leverage AI to automate A/B testing and narrow down the perfect time to send different types of emails to your unique audience.

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Annie McGreevy
Annie McGreevy
Senior editorial writer
Annie McGreevy is a senior editorial writer at Klaviyo, where she researches, interviews and writes about how businesses of all sizes can better leverage their owned marketing channels to succeed on their own terms in the current economic environment. Previously, she was a ghostwriter for thought leaders in the payments industry and taught writing to undergraduate students for more than a decade at The Ohio State University. Also a creative writer, her fiction and essays have appeared in Electric Literature, The Los Angeles Review of Books, Nouvella Books, and elsewhere. She lives in Ohio and loves the cold weather, hiking, and a good Zoom background.