Outreach Emails That Get Replies: What the 2025 Data Shows

On September 3, 2026, Validity launched Heatwave, a blocklist aimed at “unethical cold email practices including artificial domain warming,” which it said had “already listed more than 1 million domains” (Validity). Warm-up services that trade fake opens and replies between mailboxes, long sold as protection for cold email, are a listing signal. Such tools are “not safe or smart to use,” deliverability expert Al Iverson wrote, and Validity says those listings do not expire merely because the activity stops. Microsoft, meanwhile, has been rolling out a Promotions tag for bulk promotional mail in business Outlook inboxes through October (Microsoft).

Outreach that works in this environment is smaller, slower and more specific.

What a good reply rate looks like

Across 31 million emails sent by its users in 2025, Hunter found an average sequence reply rate of 4.5%, and 3% for sales outreach. Instantly puts the average at 3.43%, with the top 10% of campaigns at 10.7% or more. Both are vendor data from their own users.

List size stands out in Hunter’s numbers: sequences to 21 to 50 recipients averaged 6.2%, against 2.4% for those sent to more than 500. Small, well-researched lists tend to do better than volume.

Get the email delivered

• Authentication: set up SPF, DKIM and DMARC. Gmail’s bulk-sender rules apply to personal Gmail accounts; Google says they “don’t apply to messages sent to Google Workspace accounts,” and business inboxes run their own bulk filtering (Google).
• Complaints: Google’s target is reported spam below 0.1%, never reaching 0.3%.
• Domain and volume: custom domains averaged 5.2% replies against 2.5% for free email addresses, and reply rates peaked at 5.7% for campaigns sending 20 to 49 emails a day, Hunter found.
• Warm-up: ramp real, wanted sending slowly over several weeks. Don’t buy engagement networks.

Write for one person

In Hunter’s survey, 61% of decision makers said cold emails fail because they are not relevant and 48% blamed generic messages, while 67% said personalization using public information makes them more likely to reply. Lead with why this person, why this month and one specific ask. Instantly says its best senders average fewer than 80 words in a first email, though Hunter also found a second peak at 181 to 200 words, likely where every line is specific.

Consider switching off open tracking. Sequences with tracking enabled averaged 4.4% replies against 7.4% without it, in Hunter’s data, which does not say why. In France, the data protection authority CNIL says tracking pixels in prospecting emails need consent; the grace period for existing lists ended in July 2026.

Follow up, then stop

Hunter found three messages more than doubled replies compared with one, 6.8% against 3.3%, and that sequences following up more often did worse. Instantly says 42% of replies come after the first email and recommends four to seven touches. Three or four messages, each adding something new, is a sensible middle. Our follow-up guide covers response times and when to stop.

Know the legal line

• US: CAN-SPAM needs no prior consent but “makes no exception for business-to-business email”: honest headers and subject, a clear ad disclosure, a postal address, and a working opt-out honored within 10 business days.
• UK: under PECR you can email “any corporate body,” but sole traders and some partnerships count as individuals, and fines match UK GDPR levels (ICO).
• EU: consent rules for business email vary by country under the ePrivacy Directive.
• Canada: CASL requires consent; a published business address implies it only if the message is relevant to the person’s role (CRTC).

Our email marketing guide and subject line guide cover the rest of the inbox, and our piece on the FCC’s do-not-call rule covers phone outreach. We plan and run outreach as part of our email marketing and performance marketing work.

Frequently Asked Questions

What is a good cold email reply rate?

Above about 5% is good, and 10% or more is top tier. Hunter’s data on 31 million emails sent in 2025 puts the average sequence at 4.5%, with sales outreach at 3%. Instantly reports an average of 3.43%, a top quartile above 5.5% and a top 10% above 10.7%. Both datasets come from each vendor’s own users. Small, targeted lists do better: 6.2% for 21 to 50 recipients in Hunter’s data.

How many follow-up emails should a cold sequence have?

Three or four in total is a sensible default. Hunter found that three messages more than doubled replies compared with one, while following up more often lowered the average. Instantly found 42% of replies arrive after the first email and suggests four to seven touches. Make each message add something new, such as a relevant example or a different angle, and stop once the sequence ends or the person opts out.

Is B2B cold email legal?

It depends on where the recipient is. In the US, CAN-SPAM allows it without prior consent if headers and subject lines are honest, the email is identified as an ad, a postal address is included, and opt-outs work and are honored within 10 business days. The UK lets you email corporate bodies, but sole traders count as individuals. EU countries set their own business rules, and Canada’s CASL requires consent, implied only in narrow cases.

How long should a cold email be?

Short is the safer default. Instantly says its best senders average fewer than 80 words in a first email, and Hunter’s 2025 data shows strong reply rates at 61 to 80 words. Hunter also found a second peak at 181 to 200 words, which suggests a longer email can work when every line is specific to the reader. Name the reason for writing, why it matters to them and one clear ask.