When Are Emails Opened? Data from 3 Million Emails

Mailbutler looked at 3.1 million opened emails, sent between May and October 2026, to see when people read them. Of the emails that get opened, two thirds are opened within an hour, and nearly all first opens happen on a weekday, most of them in the morning.

• Speed: 66% of opened emails are opened within an hour, 79% within four hours, and 92% within a day. The median is 15 minutes.
• Time of day: About 36% of first opens happen between 9:00 and 13:00, and only about 1.5% between midnight and 6:00 (readers in Central Europe, local time).
• Day of the week: 93% of first opens happen from Monday to Friday. Monday is the busiest day and Friday the quietest weekday.
• Weekends: Emails sent on a weekend wait almost four times longer to be opened, with a median of about 110 minutes compared with about 30 minutes on weekdays.

Short on time? Download the infographic (PDF) with all findings at a glance.

How we did it

We analyzed aggregated, anonymized email tracking data from Mailbutler. No email content, subjects, or recipients were used, and no individual is identifiable.

• Sample: 3,087,838 emails that were opened at least once, sent by about 10,300 Mailbutler users between May and October 2026. Internal accounts are excluded.
• Speed: The time between delivery and the first open, shown with and without opens in the first minute.
• Hour and weekday: The time of the first open, converted to Central European time, for readers in Central European countries where we could identify the location of the open. These charts leave out opens within a minute of delivery; including them barely changes the picture.
• Tracking caveat: We only see emails that were opened, so the figures describe how quickly opened emails are read, not how many emails are opened.
• Automated opens: Some opens within the first minute may come from mail security scanners or Apple’s privacy features rather than people.

How fast are emails opened?

Email is a fast channel. Among emails that get opened, the median time from delivery to the first open is 15 minutes, and two thirds are opened within the first hour.

Cumulatively, 66% of opened emails are opened within an hour, 79% within four hours, and 92% within 24 hours. Only about 4% wait longer than three days.

A note on very fast opens. Almost 22% of opens happen within a minute of delivery. Some of these are probably automated, for example mail security scanners or privacy proxies. If we leave all opens under one minute out, the median rises to 38 minutes, and 57% of the remaining emails are opened within an hour, 74% within four hours, and 89% within 24 hours. The real figure for human readers lies between the two versions.

What time of day are emails opened?

For readers in Central Europe, the working morning is prime time. Opens climb steeply from 8:00, peak between 10:00 and 12:00, dip slightly at lunch, and pick up again in the early afternoon.

• About 36% of first opens fall between 9:00 and 13:00.
• Roughly 80% happen between 8:00 and 18:00.
• Fewer than 2% happen between midnight and 6:00.

The figures leave out opens within a minute of delivery. Including them barely changes the shape; the peak simply moves to 11:00 at 9.7%.

Which days, and what about the weekend?

More than 9 in 10 first opens happen on a weekday. Monday is the busiest day, and activity falls steadily towards Friday.

When you send matters less than you might think, as long as it is a weekday. Emails sent from Monday to Friday are opened at almost exactly the same pace. Weekend emails wait much longer.

These medians cover only emails that were opened. Weekend emails may also be opened less often overall, which this data cannot show.

What this means for your emails

• Expect a quick response. Most opens happen within the first hour, so write subject lines and first lines for someone reading right away.
• Aim for the working morning. Emails that arrive between 8:00 and 12:00 on a weekday meet readers when most opens happen.
• Skip the night. Almost nobody opens email between midnight and 6:00. If you write late, schedule the email for the morning rather than letting it land overnight.
• Be careful on weekends. Emails sent on a Saturday or Sunday take almost four times longer to be opened. If the timing matters, send them on Monday morning instead.
• Do not over-think Tuesday against Thursday. Weekday send days behave almost identically.
• Follow up with patience. With about 8% of opened emails read only after more than a day, a follow-up after a few days is reasonable, but not within the first hours.

Mailbutler’s Tailored Sending and Email Tracking make this easy: schedule an email for the right moment, then see when it is opened.

Short on time? Download the infographic (PDF) with all findings at a glance.

Limits of this analysis

• The data covers only emails that were opened. It says how quickly opened emails are read, not how many emails get opened.
• Some opens within the first minute may be automated, for example by security scanners or privacy features. The figures show how the results change without them.
• Hour-of-day and weekday charts cover readers in Central European countries, where we could identify the open location, and are shown in Central European time. Readers elsewhere may behave differently.
• Mailbutler users are professionals who send business email, so the findings may not apply to newsletters or consumer mailings.

About Mailbutler

Mailbutler is a leading email productivity extension for Apple Mail, Gmail, and Outlook, with email tracking, scheduled sending, templates, mail merge, signatures, and more. It has been helping people work with email for more than 11 years. The data in this post is aggregated and anonymized; no email content or personal data was used.