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Email Optimization: Testing Best Time of day and day of Week for Email Interaction

Hannah Morrell
Jan 8th, 2015
  • Estimated reading time: 4 min read
  • Hummy's

    1Tuesdays and Thursdays have the lowest engagement. 2Saturday is the optimal day for click-throughs. 3Send promotional emails Mondays at 7 p.m.
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Email Marketing

Zadorozhnyi Viktor Photo Credit: Tomislav Pinter Shutterstock

In today’s MarketingExperiments Blog post, we’re going to explore which times of the day and days of the week people are most likely to interact with their emails — two questions of optimal interest for any emailing campaign.

When do you check your personal email? Do you let it build up throughout the work week and go through it during the weekends? Do you check it on Monday when you’re also sorting through your work email? Or do you check it while you’re at lunch or on a quick, but much-needed, break from work?

Testing  the time of day when people interact with email

In email testing, we focus so much on the content and landing page of the email, but that hard work won’t pay off if email recipients don’t open or clickthrough the email. We wanted to get a better understanding of when people interact with emails to determine the best time of the day and day of the week to send promotional emails.

First, we began testing what time of day people are most likely to open and interact with emails.

Emails were currently being sent out on Mondays and Wednesdays at 7 a.m. EST. We hypothesized that by sending emails at various times throughout the day, we would learn the optimal times recipients are most likely to open and clickthrough their emails.

In an A/B split test, we sent a promotional email at 7 a.m., 3 a.m., 3 p.m. and 7 p.m. EST on a Monday. We wanted to isolate the general times of day people may be interacting with their email.

3 a.m. was tested to determine if people were more likely to interact with their emails as soon as they wake up in the morning and before they start their day, while 3 p.m. would tell us if people were checking their emails in the afternoons.

Lastly, 7 p.m. results would show that recipients were more likely to check and interact with their email in the evenings or later at night.

By sending emails at 7 p.m. EST instead of 7 a.m. EST, we saw a 12% lift in open rate:

We saw a similar lift in clickthrough rates, as the 7 p.m. send gained a 16% increase:

By testing the time of day single product promotional emails were sent, we learned that, of the times emails were sent, 7 p.m. EST was the most optimal send time in terms of both open and clickthrough rate.

Testing the day of the week when people interact most with email

Next, we began testing which day of the week email recipients are most likely to open and interact with emails. We used the same product we used in the time of day email send to lower the chance of a validity threat.

Mondays at 7 p.m. EST was the control send time, and we hypothesized that there may be a better day that resonated with visitors to open and interact with our promotional emails. We had enough traffic to send an email out at the same time every day of the week, so that’s exactly what we did.

Emails were sent out every day of the week at 7 p.m. EST. When we looked at open rate, we saw that every treatment underperformed or didn’t validate:

When we looked at clickthrough rates comparing clicks to delivered emails, we saw that Wednesdays and the weekend resulted in higher email interaction. Tuesdays and Thursdays had the lowest interaction:

In this sequence of tests, we learned that sending emails at 7 p.m. instead of 7 a.m. showed a 12% lift in open rate and a 16% lift in clickthrough rate.

Saturday was the optimal day for visitors to interact with and clickthrough to the landing page, as it outperformed the emails sent on Monday by 6.37% and validated at 99% Level of Confidence.

What we learned

Also, recipients are more likely to open an email on Monday, but they are more inclined to interact with it on the weekends, as Saturday showed a 6% lift in clickthrough.

Overall, Mondays at 7 p.m. is the optimal promotional email send time for this audience. It is important to remember that every target audience is different and the best way to know the optimal time and day to send your emails is by testing.

Next time you open, delete and clickthrough your emails, remember that you are not alone. Several others are doing the same thing as you, and you can use that to your advantage in your next email campaign.

These tests are just one example of how the time of day and day of the week emails are sent could significantly impact your email campaign. The next test you run, don’t just think about testing copy and subject lines, but consider testing when your audience is most likely to open and clickthrough the email.

This article was written by Hannah Morrell and published by MarketingExperiments, the first internet based research lab to conduct experiments in optimizing sales and marketing processes.