The open rate of a business email depends in part on when it’s sent. A message received at the right time is more likely to be read, clicked and acted on. But the idea of an ideal send time is based on specific mechanisms that you need to understand before choosing a time slot.
Why open rates are no longer enough to judge a send time
Before looking for the best time to send an email, you need to know what you’re measuring. The open rate was long the main metric for evaluating email performance. An invisible pixel embedded in the message loads when the recipient opens the email, and the system records this action.
This mechanism has become less reliable. Apple Mail Privacy Protection can load a message’s content in the background, without it actually being read. So an increase in open rates after changing the send time doesn’t prove that the new time slot is more effective.
Clicks and conversions provide a more accurate picture of genuine engagement. To compare two send times, keep the content and audience the same, and track concrete actions (clicking a link, replying or making a purchase) rather than opens alone. As Nefa Blog’s article on business emails explains, sending an email late can also affect how the recipient perceives it, beyond what the numbers alone show.
Email send times: what aggregated data shows
Most studies on the subject point to two morning windows. The first is between 8 a.m. and 10 a.m., when professionals check their inboxes as they arrive at the office or start their day. The second, less frequently mentioned, is between 1 p.m. and 2 p.m., after the lunch break.
As for days of the week, Tuesday and Thursday are regularly cited as the days with the highest engagement in B2B. Monday is weighed down by the backlog of weekend messages. On Friday, attention tends to wane as the day goes on.
These general trends present a logical problem. If every sender schedules their emails for Tuesday at 9 a.m., recipients’ inboxes become saturated at exactly that time. A time slot known to work well loses its advantage when everyone uses it.
B2B and B2C: two different rhythms
In B2B, emails sent during business hours are more likely to get noticed because recipients are already at their screens for work. Weekend send times rarely produce good results in this context.
In B2C, behavior varies more. A promotional email sent on Saturday morning can work very well if the target audience checks personal messages then. The early evening slot, between 5 p.m. and 7 p.m., also reaches consumers unwinding after work.
Deliverability and authentication: the invisible filter before send time
Choosing the right time slot has no effect if the message doesn’t reach the inbox. Since February 2024, Gmail and Yahoo have enforced new requirements for bulk senders. These rules cover domain authentication (SPF, DKIM, DMARC) and making it easy to unsubscribe.
Senders who don’t comply may face temporary or permanent rejections. In practice, the message is blocked or redirected to the spam folder before send time even comes into play.
Before concluding that poor results are due to timing, check three things:
- Domain authentication is correctly configured (SPF and DKIM records and a DMARC policy published in DNS)
- The unsubscribe link is visible and functional in every email, in line with Gmail and Yahoo requirements
- The spam complaint rate stays below the critical threshold, since a damaged sender reputation affects every email, regardless of the time slot
A technically flawless email sent at an average time will perform better than a poorly authenticated message sent at the supposedly perfect time.
A/B testing send times: how to find the right time slot for your audience
Industry averages provide a starting point, not a definitive answer. The only reliable way to determine the best time to email a particular audience is to A/B test send times.
The principle is simple: send the same email, with the same subject line and content, to two randomly selected groups from the same list, but at two different times. The only variable is the send time.
What to measure (and what to ignore)
Given the limitations of open rates discussed above, it’s better to evaluate the test based on clicks or a specific business goal (a completed form, a booked appointment or a purchase). Comparing clicks across two time slots provides a more reliable signal than comparing opens.
A single test isn’t enough. Email-checking habits vary depending on the time of year, holidays and industry events. Repeating the test a few weeks later helps confirm or challenge the initial results.
Time zones and segmentation
If your contact list spans multiple time zones, a single email sent at 9 a.m. Paris time arrives at 3 a.m. on the US East Coast. Segmenting the list by time zone and scheduling staggered sends prevents your message from getting buried under emails that arrived during the recipient’s night.
Most email marketing tools offer this send-time optimization feature, based on location or individual engagement history. This approach is a better alternative to searching for a universal time slot.
The send time of a business email is one lever among many, after technical deliverability and content relevance. A time slot tested with your own audience, evaluated based on clicks rather than opens, and adjusted to recipients’ time zones will produce more lasting results than a schedule copied from a general study.
