The best time to send email to a B2B list is mid-morning on a weekday, around 10 a.m. in the recipient’s own time zone. That is what Mailchimp’s send time data recommends, and it matches the best window in Belkins’ study of 7.5 million cold emails. The studies agree on the hour far more than on the day. Tuesday, Wednesday, Thursday and Friday each win in at least one study, and the gaps between them are small.
Two warnings before the data. First, most “best time” articles repeat numbers from 2013 to 2018 without saying so. Every study below has its sample, its metric and its date. Second, any study that ranks send times by open rate is now measuring a lot of machines. Apple Mail opens are recorded whether or not a person read the email, so trust studies that use clicks, replies or conversions more.
What do the studies say about the best time to send email?
| Study | Sample | Metric | Best day | Best time |
|---|---|---|---|---|
| Mailchimp (undated) | Send time optimization data, size not given | Engagement | Tuesday, Wednesday, Thursday | 10 a.m. recipient’s time |
| Omnisend (May 2026) | About 26 billion emails | Opens, clicks, conversions | Tuesday for opens (31.27%) and clicks (0.81%); Friday for conversions (0.081%) | Friday 7 a.m. for conversions (0.138%) |
| Klaviyo (July 2024) | Thousands of 2023 campaigns, machine opens removed | Opens, clicks | Wednesday and Thursday overall; Tuesday opens 12.52%, Wednesday clicks 2.18% | Not given |
| MailerLite (Dec 2025) | 2,138,817 campaigns, US, UK, AU, CA, Dec 2024 to Nov 2025 | Opens, clicks | Friday (49.72% opens, 8.09% clicks) | Clicks peak 8 to 9 p.m. |
| GetResponse (2023 data) | More than 4.4 billion messages | Opens, clicks | Tuesday, by a small margin | 4 to 6 a.m. and 5 to 7 p.m. |
| Belkins (2025 data, updated June 2026) | 7.5 million B2B cold emails | Replies, meetings | Wednesday and Thursday (0.48% reply rate) | 8 a.m. to 12 p.m. (0.54% reply rate) |
| Instantly (Sept 2026) | Its 2026 benchmark report | Replies | Tuesday and Wednesday, Wednesday best | Not given |
| Yesware (Nov 2020) | Reply data, about 46,000 replies at the peak hour | Replies | Monday and Tuesday most active, Friday least | 1 p.m., then 11 a.m. |
| Campaign Monitor (2013 data, published 2019) | More than 192 million opens | Opens | Not given | Over half of opens 9 a.m. to 5 p.m. |
Read the table this way. The B2B and sales studies (Mailchimp, Belkins, Yesware) cluster around late morning on a weekday. The ecommerce-heavy datasets (Omnisend, MailerLite, GetResponse) find more activity early in the morning and in the evening, when people shop and read newsletters at home. Your list decides which group you belong to.
Why do the studies disagree on the best day?
Three reasons, and none of them is that one study is wrong.
They sample different senders. Omnisend and Klaviyo serve ecommerce stores. Belkins sends B2B cold email for clients. A Friday sale email and a Tuesday sales email are not the same behavior.
They measure different things. Opens, clicks, conversions and replies each peak at a different time. Omnisend’s own data has Tuesday best for opens and Friday best for conversions.
The gaps are small. In Belkins’ data, Monday and Tuesday sit at 0.45%, Wednesday and Thursday at 0.48%, and Friday at 0.44%. That spread is smaller than the effect of a better list or a better first line. Belkins concludes that “time of day matters more than day of week”.
Why do open rates mislead send-time studies now?
In June 2021 Apple announced that Mail Privacy Protection “stops senders from using invisible pixels to collect information about the user”. In practice, Apple Mail downloads images, tracking pixels included, in the background. The email platform records an open at that moment, whether or not anyone read the message.
The scale is large. Litmus counted over 1.5 billion opens in September 2026, and Apple accounted for 76.56% of them, against 16.10% for Gmail and 3.48% for Outlook. Litmus notes that “privacy-impacted opens are included in Apple Mail opens.”
So a study that ranks hours by open rate partly ranks the hours when Apple’s servers fetched mail. Klaviyo removed machine opens from its analysis, and MailerLite recommends A/B testing by click rate rather than open rate. For your own tests, use clicks for newsletters and replies or meetings for sales email. Our glossary entry on open rate covers what the number still tells you.
What is the best time to send a cold email?
Morning, on a weekday, in the prospect’s time zone. The cold email data is thinner than the newsletter data, but it is better: it measures replies, which machines do not fake.
| Window (Belkins, 2025) | Reply rate |
|---|---|
| 8 a.m. to 12 p.m. | 0.54% |
| 5 a.m. to 8 a.m. | 0.52% |
| Afternoon | 0.47% |
| Night | 0.40% |
Source: Belkins, 7.5 million cold emails sent January to November 2025. Reply rate is replies divided by emails sent.
Belkins also tracked meetings. Morning and early morning sends both had a 0.4% meeting rate, which it calls four times higher than every other window. By day, Wednesday and Thursday tied for the best reply rate at 0.48%. Sunday showed 0.57%, but on very low volume, so treat it as noise.
Two more points from the sales data:
- The first email does most of the work. Instantly reports that 58% of replies came from the first email in a sequence. Timing the first touch well matters more than timing the fourth. Our guide to cold email follow-ups covers the rest of the sequence.
- Replies come fast or not at all. Yesware found that “in just the first hour, 75% of emails are opened and 42% of emails are replied to”. Send when the prospect is at their desk, not at 2 a.m. their time.
Sending cold email at scale also has rules that matter more than timing. Since February 2024, Gmail requires senders of more than 5,000 messages a day to keep spam rates below 0.10% and never reach 0.30%, and to set up SPF, DKIM, DMARC and one-click unsubscribe. A perfectly timed email that lands in spam gets no replies.
How should you time different kinds of email?
| Email type | When to send | Why |
|---|---|---|
| B2B newsletter | Tuesday to Thursday, about 10 a.m. recipient’s time | Mailchimp’s recommendation; work-hours reading |
| Cold email, first touch | 8 a.m. to 12 p.m., Wednesday or Thursday | Belkins’ best reply and meeting windows |
| Follow-up in a live deal | Within the hour of the call | The buyer is still thinking about it |
| Product and lifecycle email | Triggered by the user’s action | The action is the timing; a fixed hour adds delay |
| Event invitation | Weekday morning, two to four weeks before | Gives time to plan; repeat to non-openers by clicks |
| Ecommerce promotion | Test early morning and evening | Omnisend and MailerLite found activity outside work hours |
For lifecycle and nurture email, the trigger matters far more than the clock. A welcome email sent the minute someone signs up beats one sent at “the best time” the next morning. Our guide to B2B SaaS email marketing covers which emails to trigger and which to schedule.
How do you find the best send time for your own list?
- Pick one metric that a person creates. Clicks for newsletters, replies for sales email, meetings booked if you can track them.
- Split one list at random into two or three groups. Send the same email to each group at a different hour on the same day.
- Use the recipient’s time zone. Most platforms can schedule by contact time zone. Without it, “10 a.m.” is 7 a.m. on the West Coast.
- Repeat it at least three times. One send can be thrown off by a holiday or a news event.
- Then test the day, holding the hour that won.
- Write down the result and when you ran it. Lists change; rerun the test every six months.
A send-time test, worked through
Illustrative, not a benchmark. The company is fictional.
Corvel Data sends a monthly product newsletter to 12,000 operations leaders, mostly in the US. It always sent at 8 a.m. Eastern. The team split the list into three random groups of 4,000 and sent at three local times:
| 8 a.m. Eastern (fixed) | 10 a.m. recipient’s time | 2 p.m. recipient’s time | |
|---|---|---|---|
| Recipients | 4,000 | 4,000 | 4,000 |
| Clicks | 96 (2.4%) | 128 (3.2%) | 104 (2.6%) |
The 10 a.m. local group won on clicks in this send. The team reran the test the next two months before changing the default, because a 0.8-point gap on one send could still be chance. Opens were ignored: they were almost identical across the three groups, which is what you would expect when most opens come from Apple’s servers.
How Growigami handles send times
Our email nurture service schedules newsletters by recipient time zone, triggers lifecycle email from product and CRM events instead of fixed hours, and reports on clicks, replies and meetings rather than opens. For cold outbound, our outbound service sends first touches in the prospect’s working morning and pairs timing with subject lines that name the reason for writing. See our cold email subject lines for that half of the job.
Frequently asked
What is the best time to send an email?
For most B2B lists, mid-morning on a weekday in the recipient's own time zone. Mailchimp's send time data points to 10 a.m. local time on Tuesday, Wednesday or Thursday, and Belkins found the highest cold email reply rate between 8 a.m. and 12 p.m. across 7.5 million emails sent in 2025. The day matters less than the hour, and your own list can differ.
What is the best day to send an email?
The studies do not agree. Omnisend found Tuesday best for opens and clicks across about 26 billion emails, Klaviyo found Wednesday and Thursday strongest, and MailerLite found Friday had the highest open and click rates across 2.1 million campaigns. The gaps between weekdays are small in every study, so test it on your own list.
What is the best time to send a cold email?
In Belkins' 2025 data (7.5 million cold emails), 8 a.m. to 12 p.m. had the highest reply rate at 0.54%, and morning sends had a 0.4% meeting rate, four times other windows. Wednesday and Thursday tied for the best weekday at 0.48%. Send in the prospect's time zone, not yours.
Is it better to send emails in the morning or afternoon?
Morning, in most of the data. Mailchimp points to 10 a.m., Belkins found morning sends got the most cold email replies, and Yesware's reply data peaked around 11 a.m. and 1 p.m. MailerLite is the exception: its clicks peaked between 8 and 9 p.m., which reflects newsletters read at home more than work email.
Do open rates still tell you the best send time?
Not reliably. Apple's Mail Privacy Protection, launched in 2021, loads tracking pixels in the background, so an open can be recorded when nobody read the email. Litmus reported Apple at 76.56% of the opens it tracked in September 2026. Judge send times on clicks, replies and meetings instead.
Should I use send time optimization?
If your platform offers it and your list is large, yes, as a test against a fixed time. Send time optimization picks an hour per contact from their past engagement. Check how it measures engagement: if it learns from opens, Apple's machine opens can mislead it.
