What's the best time to send marketing emails?

This is for founders who've read three "best time to send" articles with three different answers and want to know what to actually do on their own list.

Why is there no single best time to send marketing emails?

Every "best time" stat you've read is an average across other people's lists. Your customers don't read email on that average's schedule.

So I don't give clients a best hour. Each account has its own best time. Most of them tend to peak during the windows you'd expect: lunch, after work, or the weekend before people head out. But you still need to test send times on your own list. Only then will you know whether there's a best moment for specific content, like a promotion or a discount.

What send times do I usually see win?

Here's my observation across the accounts I work in, not a measured stat: for primary campaigns, the best send time is usually somewhere between 10 AM and 12 PM.

But in a lot of cases, a particular brand's best time is 9 PM, or 3 PM. Those aren't small differences. If your list is a 9 PM list and you've been sending at 10 AM for two years, you'd never know unless you tested it.

That's the whole reason to test instead of copying a chart.

How do you test send time on your own list?

Keep it simple. Here's how I'd run it:

1. Split the audience 50/50. Use a large, engaged segment, so each half gets a real number of people.
2. Send the same email at two times. Same email, same subject line, same segment. Only the time changes. My go-to first test is 12 PM against 9 PM.
3. Compare the revenue. Look at what each half actually made.
4. Run it twice. You don't need several weeks. Two weeks is enough: one send in week one and another in week two, with the audience split 50/50 each time.
5. Skip holidays and big promos. A Black Friday send tells you about Black Friday, not about a normal Tuesday.

You don't need a special feature for this. Klaviyo's campaign A/B test has a send time option. Per Klaviyo, you keep the content and subject line exactly the same in both versions, send time tests always go to 100% of recipients, and the times use your account's time zone. If you're not sure where to start, Klaviyo suggests trying an evening time, which lines up with my 9 PM test.

If the results keep coming back close, that's your answer. Pick the time that's easiest to run and put your effort into who you're sending to and what the email says.

What matters more than send time?

Two things, and I'd fix them first.

Who you send to. At a fitness tech brand, an engaged send to 7,145 people earned $0.19 per person. A full-list blast to 49,475 people earned $0.04. No send time closes a gap like that. I cover how I split a list in email segmentation for ecommerce.

What the email says. Across 3,176 Klaviyo campaigns from 9 brands, subject lines that named the offer earned 1.46x the same brand's typical revenue per email. Launch-style lines earned 1.26x. That spread comes from what's in the email, not when it landed.

If you want to compare results the right way, my open rate vs click rate post explains why I don't let opens alone pick a winner.

How does Klaviyo Smart Send Time work?

Smart Send Time is Klaviyo's way of finding one best time for your audience. Per Klaviyo's help center, it runs in three phases:

1. Exploratory: Klaviyo tests sending times across all 24 hours of the day, with each person randomly assigned a time in their local time zone.
2. Focused: Klaviyo picks the time with the highest engagement and splits people into three groups: that time, 2 hours before, and 2 hours after.
3. Optimal: once it finds the best time, you can send at that time to audiences of any size.

The requirements are the part founders miss:

• Audience size: the exploratory and focused tests need campaigns going to 12,000 people or more. Between 12,000 and 17,999 people, Klaviyo says you'll need 4 to 5 exploratory sends.
• Email only. Klaviyo says Smart Send Time is only available for email.
• No A/B tests on Smart Send Time emails.
• Keep your normal cadence. Klaviyo warns against sending more often just to make the model work faster.
• Not for time-sensitive content like flash sales or deadline announcements, and not around major holidays.

I do use Smart Send Time in accounts, as a way to test and find the winning send time. But not exclusively, and not for a long stretch. Once I have the winning time, I want to lean into it.

What about Klaviyo Personalized Send Time?

Personalized Send Time picks a time for each person instead of one time for everyone. Here's what Klaviyo's help center says:

• Plans: it's available on the Personalization or Advanced KDP packages, so it's an add-on, not part of the standard plan.
• Channels: email, SMS, push and WhatsApp campaigns. It's not available in flows yet.
• Scheduling: you have to schedule at least one day ahead. No same-day sends.
• What it optimizes for: opens, clicks and placed order rate, learned from your account's engagement and profile data.
• Measurement: a random group of recipients is held out as a control. Klaviyo says to allow about 24 hours after the last message goes out before the results show.
• Not for urgent sends: it isn't suited to flash sales or announcements where everyone needs the message at the same clock time.

If you have it, check the control group results on your own account before deciding it's worth paying for.

When does send time really matter?

When the email has a clock in it.

• Deadline sends. "Ends at midnight" only works if it lands with time to act. At a snack brand, "Your special discount ends at Midnight!" made $11,560, about 7.2x that brand's typical email.
• Launches and restocks. People want news the day it drops. Send it when it's live.
• BFCM. Black Friday is Nov 27 and Cyber Monday is Nov 30 this year. On those days, the time of each send is part of the plan, especially if you send more than once a day. My cadence guide is in how many emails per week to send.

Both of Klaviyo's send time features say to skip time-sensitive sends. For these, pick the time yourself and send to the whole segment at once.

Where these numbers come from

The subject line multiples come from 3,176 Klaviyo campaigns across 9 brands, each measured against that brand's own typical revenue per email. The $0.19 vs $0.04 comparison and the deadline email are single-brand results. The 10 AM to 12 PM window is my observation from client accounts, not a measured stat. Treat all of it as directional. For how brands compare on revenue per email, see my CPG email marketing benchmarks.

FAQ

WRITTEN BY Jack White

Founder of Bardown Digital, a Chicago-based Klaviyo email and retention agency for Shopify brands. He's worked with brands doing $500K to $100M a year, with $100M+ in email-attributed revenue across them.

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