How to Build Your Email List

Every email list shrinks on its own, no matter how good your content is. The main reason is that people change jobs. When a contact moves to a new company, their email address dies even though they never unsubscribed.

The most cited dataset comes from ZeroBounce, a list-verification vendor, which reports annual decay in the 22% to 28% range. That range is plausible because it lines up with government employment data. The U.S. Bureau of Labor Statistics reports a median employee tenure of 3.9 years, and Statistics Canada reports 13.2% of Canadian workers with less than one year of tenure. Job changes alone will put a meaningful share of your contact data out of date every year.

Many organizations don’t act on this. A 2026 Mailgun survey found 39% of senders clean their email lists rarely or never, leaving dead email addresses and inactive subscribers in place.

So the first step in growing your email database is maintenance. Remove addresses that bounce or fail email verification, review inactive subscribers on a regular schedule, and plan for new subscribers knowing that roughly a quarter of your mailing list will need replacing each year. Growth that ignores decay looks like progress until the numbers stall.

Your own website is where most email signups happen, and it’s also where the strongest evidence in this field applies.

A peer-reviewed 2014 study presented at CHI, the leading academic conference on human-computer interaction, tested web forms against established usability guidelines. Forms that followed the guidelines achieved a 78% one-try completion rate. Forms that didn’t follow the guidelines only achieved 42%.

That makes form design the safest place to start. Keep your signup forms short and clear, and make them forgiving when someone mistypes. Trim required fields and don’t ask for more contact information than you need at signup. You can collect additional information such as role, company size, and interests at a later time. A form that is hard to complete loses a potential subscriber who already intended to sign up.

Consider double opt-in, where a new subscriber confirms their email address by clicking a link. Vendor advice on it contradicts itself, but Validity’s 2025 deliverability benchmark reports that major mailbox providers favour senders who use it.

Sooner or later someone asks whether it is legal to buy an email list. Vendors sell business email lists labelled as compliant, and buying one looks like a shortcut. The answer depends on jurisdiction, but the pattern across Canada, the United States, and Europe points the same way: build your email list from people who gave consent to you.

In Canada, CASL ties consent to the specific organization that collected it. Buying a list of email addresses, outside the sale of a business as a whole, risks not being compliant with CASL. The burden of proof sits with whoever sends the message, so you, the buyer, must be able to substantiate consent if challenged.

Not having that proof can be expensive. On 1 October 2026, the Canadian Radio-television and Telecommunications Commission fined Pizza Hut $500,000 for sending commercial electronic messages that violated CASL rules. If you think it only happens to large corporations, think again. On 7 October 2026, a window cleaning company in Ottawa got fined $10,000 for violating CASL rules. 

Your email marketing platform draws the line too. Every major email service provider we reviewed, including Mailchimp, HubSpot, Klaviyo, ActiveCampaign, and Constant Contact, bans purchased email lists and rented lists. ActiveCampaign’s policy states that collecting business cards does not constitute opt-in, and Constant Contact confirms LinkedIn connections don’t qualify as consent.

In practice, that means three habits. Ask for consent at the point of contact, including at events and on calls, rather than adding people afterward. Record when and how each person opted in, so you can show it if asked. And give new contacts from trade shows or LinkedIn a clear invitation to subscribe instead of adding them directly.

There are several ways to grow your email list, and each one works by giving people a reason to share their email address. You can offer gated content like a guide or checklist, attach a content upgrade to a popular blog post, build an interactive tool such as a pricing calculator or quiz, host webinars and events, or pay for reach through LinkedIn lead forms and Facebook ads.

Vendors often claim one format clearly outperforms the others, but those claims usually come from companies selling that format, and their benchmarks disagree with each other. The reliable approach is to choose two options that fit the roles you want to reach and what they need to know, run them on pages or channels with steady traffic, and compare the signups and lead quality each one produces. Keep the winner and test the next idea against it. After two or three rounds, your own numbers will guide you better than any published benchmark.

Here are the main options to consider: