How does email marketing generate leads?
Email marketing brings in B2B leads by two routes. The first is a list of people who chose to hear from you: newsletter subscribers, people who downloaded something, people you met at an event who said yes. The second is cold email, one-to-one messages to people who never signed up. They follow different rules, and they produce leads at different speeds. The table is our judgement for a team of one to five people.
| Opt-in list (newsletter, downloads) | Cold email | |
|---|---|---|
| Who you write to | People who signed up | People you picked who don't know you yet |
| What a lead looks like | A click on a call-to-action, a reply, a booked call | A reply |
| Time to the first lead | Slow: you need a list first | Days, once you have 100 well-picked people |
| Main risk | A list that reads but never buys | Spam complaints that hurt your domain |
| Best for | Buyers who take months to decide | A known, small set of buyers you can name |
The two routes cover different timelines. Cold email starts conversations this month. A list keeps the people who weren't ready in touch until they are.
How many leads will an email list bring in?
Expect a small number of clicks per send, and treat each one as a lead to look at. Two large benchmark sets give the range:
- Mailchimp's benchmarks cover campaigns sent to at least 1,000 subscribers, with data as of December 2023. The Business + Finance industry averaged a 31.35% open rate, a 2.78% click rate and a 0.15% unsubscribe rate. All users averaged 35.63%, 2.62% and 0.22%.
- MailerLite's 2025 benchmarks cover over 3.6 million campaigns from 181,000 approved accounts, December 2024 to November 2025, and its method note says it shows the median for each figure. The click rate across all campaigns was 2.09%. By industry: consulting 2.41%, business and finance 2.37%, marketing and advertising 1.30%, software and web apps 1.15%.
Both are vendors reporting on their own customers, and MailerLite measures clicks against all recipients while Mailchimp measures them against delivered emails, so read them as a range, not a target.
A worked example. Northwind Ltd (a sample company) has 800 subscribers and sends one email a month:
| Click rate used | Arithmetic | People who click | Worth a personal follow-up (assume 1 in 5) |
|---|---|---|---|
| 1.15% (MailerLite, software) | 800 x 0.0115 = 9.2 | About 9 | 9.2 / 5 = 1.8, about 2 |
| 2.41% (MailerLite, consulting) | 800 x 0.0241 = 19.3 | About 19 | 19.3 / 5 = 3.9, about 4 |
| 2.78% (Mailchimp, Business + Finance) | 800 x 0.0278 = 22.2 | About 22 | 22.2 / 5 = 4.4, about 4 |
So 800 subscribers might give Northwind two to four people a month worth writing to personally. The cost side: at MailerLite's 0.22% median unsubscribe rate, 800 x 0.0022 = 1.8 people leave per send, about 21 over twelve sends if the list didn't grow. The "1 in 5" is our assumption; replace it with your own count after three sends.
Why are open rates the wrong signal for leads?
Because Apple's Mail Privacy Protection can record an open when no person read the email. Apple's iPhone guide to Mail Privacy Protection says the feature hides the reader's IP address and stops senders seeing whether a message was opened. It also notes that the protection doesn't cover links or attachments, which is why clicks still mean something.
The benchmark publishers say the same. MailerLite's report says Mail Privacy Protection marks emails sent to Apple Mail clients as opened, so real open rates are lower than dashboards show, and it calls click rate the most accurate engagement measure. Mailchimp's page warns that its open rates may be affected by the same feature. A 43% open rate (MailerLite's 2025 median was 43.46%) tells you little about who is interested.
Count these instead, per send:
- Clicks on the one link that matters, such as a pricing page, a booking link or a case study, not every click.
- Replies. A reply is the strongest signal an opt-in list can give.
- Calls booked by people on the list, from your calendar.
Open tracking has a cost in cold email as well; our post on whether open tracking hurts cold email deliverability covers it.
How do you turn subscribers into leads?
Ask a question they can answer by hitting reply, then follow up by hand with everyone who answers. A newsletter that only broadcasts gives you readers. One question turns some of them into conversations, and the answers tell you who is a buyer.
When someone replies, answer within a day, as a person, from the same address. Log each reply and click on the key link against the contact, so you can see who has engaged three times in a quarter. If you still need people to sign up in the first place, our sibling post explains what a lead magnet is, with real examples and the rules.
Can you use cold email for lead generation?
Yes, as long as every message follows the law where the recipient is and the limits the inbox providers set. This is a summary for US senders and Gmail and Yahoo inboxes, not legal advice.
The FTC's CAN-SPAM compliance guide is direct on the point small B2B teams most often get wrong: "The law makes no exception for business-to-business email." Its requirements include no false or misleading header information, identifying the message as an ad, telling recipients where you're located, telling them how to opt out, and honouring opt-outs within 10 business days. It says each separate email in violation is subject to penalties of up to $53,088.
The inbox providers add their own lines:
| Rule | Gmail | Yahoo |
|---|---|---|
| Spam complaint rate | Below 0.3% for all senders; its monitoring section says below 0.10%, and avoid ever reaching 0.30% | Below 0.3% |
| Authentication | SPF or DKIM for all senders; SPF, DKIM and DMARC above 5,000 messages a day to Gmail | SPF or DKIM for all senders; SPF, DKIM and a DMARC policy of at least p=none for bulk senders |
| Unsubscribe | One-click unsubscribe and a visible link in marketing messages above 5,000 a day | For bulk senders: one-click list-unsubscribe header, and honour unsubscribes within 2 days |
Sources: Google's email sender guidelines and Yahoo's sender best practices, both checked 5 November 2026. Google's page also says plainly: "Don't purchase email addresses from other companies." In numbers, 0.3% of 1,000 emails delivered to Gmail is 3 spam reports.
For the UK and EU, read our comparison of whether cold email is legal under GDPR, PECR and CAN-SPAM before you add anyone there to a list. To build a cold list worth sending to, start from our guide on where to find leads for cold email without junk lists. If you want that step done for you, Siela's Lead Finder looks for people with a reason to hear from you now and emails them from a Gmail mailbox you connect, at up to 100 emails per mailbox a day.
What to do this week
Check your sending domain
Confirm SPF and DKIM are set up; Google asks every sender for at least one of the two. Add DMARC now rather than when you pass 5,000 a day.
Rewrite your welcome email
Use the template above. One question, answered by reply.
Cut your next send to one ask
Pick one link that signals buying interest, such as pricing or a booking page, and make it the only call-to-action.
Set up a lead log
One row per person who clicked the key link or replied: name, company, what they did, date, your follow-up. Keep it in your CRM; Siela's built-in CRM, for example, has email sequences, bulk campaigns and click tracking.
Pick 50 cold prospects with a reason to write
A job ad, a post about the problem, a new role. Write one plain email to each, with your postal address and an opt-out line.
After a month, compare the two routes by one number: conversations started per hour you spent. Keep the one that wins, and keep the list running for the people who aren't ready yet.
Frequently asked questions
Is email marketing good for B2B lead generation?
Yes, if you measure it by conversations. A list keeps people in touch until they are ready to buy, and each reply or click on a buying link is a lead to follow up by hand. Cold email starts conversations faster but carries more risk to your sending domain. A small team can use cold email for this month's pipeline and a list for buyers who decide slowly.
How many subscribers do you need before email brings in leads?
There is no fixed number, but the arithmetic is simple: subscribers times click rate. Using the click rates quoted from Mailchimp and MailerLite, 1.15% to 2.78%, 300 subscribers give roughly 3 to 8 clicks a send (300 x 0.0115 = 3.5; 300 x 0.0278 = 8.3). Below a few hundred, consider a personal note to each new subscriber instead of a newsletter.
Is a 40% email open rate good?
It may mean less than it seems. MailerLite's 2025 median open rate was 43.46%, and the company says Apple's Mail Privacy Protection marks many emails as opened automatically, so real open rates are lower. Clicks on a buying link and replies tell you far more about who is interested than opens do.
What is the difference between email marketing and cold email?
Email marketing usually means sending to people who signed up, such as newsletter subscribers or people who downloaded something. Cold email is one-to-one outreach to people who never signed up. In the US both must follow CAN-SPAM, including an opt-out and a postal address. Rules outside the US differ, so check them before you write to people in the UK or EU.
Which email metric shows someone is a lead?
A reply is the clearest sign, followed by a click on a page that signals buying interest, such as pricing or a booking link. Count those per send rather than total clicks. Someone who replies or clicks a buying link two or three times in a quarter is worth a personal email that asks whether a short call would help.
Sources
- Mailchimp: Email marketing benchmarks (data as of December 2023) (checked 5 Nov 2026)
- MailerLite: Email marketing benchmarks 2026 (data Dec 2024 to Nov 2025) (updated 7 Apr 2026, checked 5 Nov 2026)
- Apple: Use Mail Privacy Protection on iPhone (checked 5 Nov 2026)
- Google: Email sender guidelines (checked 5 Nov 2026)
- Yahoo: Sender best practices (checked 5 Nov 2026)
- FTC: CAN-SPAM Act compliance guide for business (checked 5 Nov 2026)