Email advertising is any paid promotion delivered to someone’s inbox, whether you send it to your own subscriber list or pay to appear in someone else’s. It covers a wide range of tactics: newsletters you build and send yourself, sponsored placements inside third-party newsletters, and inbox ads that show up in platforms like Gmail or Outlook through paid ad networks. The common thread is using email as the channel to put a commercial message in front of a targeted audience.
How Email Advertising Works
There are two broad approaches, and they work very differently behind the scenes.
The first is sending to your own list. You collect email addresses (through signup forms, purchases, or lead magnets), then send promotional messages directly to those subscribers. This is what most people picture when they hear “email marketing.” You control the design, the timing, and the audience, but you need permission from every recipient before you send anything.
The second approach is paying for placement in someone else’s inbox. If you don’t have a list, or you want to reach people outside it, platforms like Google Ads and Microsoft Advertising let you run inbox ads that appear in Gmail or Outlook. These look similar to regular emails but are labeled as ads. You bid on targeting criteria (demographics, interests, keywords) the same way you would with search or display ads. It’s essentially pay-per-click advertising that happens to land in an inbox instead of on a search results page. You can also pay to sponsor a slot in an established newsletter with an audience that matches your customer profile.
Common Formats
- Promotional emails: Sales announcements, discount codes, product launches, or seasonal offers sent to your subscriber list.
- Newsletter sponsorships: A paid mention, banner, or dedicated section inside a third-party newsletter. You pay the newsletter publisher, and your ad goes out to their subscribers.
- Gmail and Outlook inbox ads: Native-looking ads managed through Google Ads or Microsoft Advertising. They appear at the top of a user’s Promotions or inbox tab and expand into a full email-style layout when clicked.
- Dedicated sends: A third-party list owner sends an entire email on your behalf to their subscribers. You typically provide the creative, and they handle the send.
What It Costs
Pricing depends on the format. For emails you send from your own list, most platforms use a tiered cost-per-thousand (CPM) model. Sending 1,000 to 10,000 emails typically runs $10 to $12 per thousand. At higher volumes, the rate drops: 50,000 to 250,000 emails often falls in the $6 to $8 range, and anything above that is usually a negotiated rate. Some services sell pay-as-you-go credits instead of monthly plans, charging roughly $0.03 per email at low volumes and under a penny per email once you’re sending tens of thousands.
For inbox ads through Google or Microsoft, you pay per click or per thousand impressions, just like other digital ads. Rates vary by industry and competition, but the bidding mechanics are identical to running a display or search campaign.
Newsletter sponsorships are priced differently. Publishers typically quote a flat fee per send or a CPM based on their list size. Niche newsletters with a highly engaged audience can charge premium rates, while broader lists may be cheaper per subscriber but less targeted.
Regardless of format, email advertising delivers strong returns relative to other channels. The commonly cited benchmark is roughly $36 to $38 in revenue for every $1 spent, though your actual results will vary with your offer, your audience, and how well your emails are written.
Legal Requirements Under CAN-SPAM
If you’re sending commercial email to U.S. recipients, the CAN-SPAM Act sets the ground rules. Violating it can result in penalties of over $50,000 per email, so it’s worth knowing the basics.
Every commercial email must include three things: your valid physical postal address (a street address, P.O. box, or registered private mailbox all qualify), a clear disclosure that the message is an advertisement, and an easy way for the recipient to opt out of future messages. The opt-out mechanism can be a reply-to address or a single web page, but you can’t require the recipient to pay a fee, hand over personal information beyond their email address, or jump through multiple steps to unsubscribe. Once someone opts out, you have 10 business days to stop sending them messages. Your opt-out link must remain functional for at least 30 days after the email goes out.
Beyond disclosures, the law also requires accuracy. Your “From” name, reply-to address, and routing information must correctly identify who sent the message. Subject lines must reflect what’s actually inside the email. Misleading headers or deceptive subject lines are violations on their own, separate from the disclosure requirements.
What to Measure
The core metrics are straightforward. Open rate tells you what percentage of recipients actually looked at your email. Click-through rate measures how many people clicked a link inside it. Conversion rate tracks how many of those clicks turned into the action you wanted, whether that’s a purchase, a signup, or a download. Unsubscribe rate shows how many people opted out after receiving a particular message.
For inbox ads and newsletter sponsorships, you’ll also want to track cost per click and cost per acquisition so you can compare performance against your other paid channels. Most email platforms and ad networks provide these numbers in their dashboards, so you won’t need to calculate them manually.
When Email Advertising Makes Sense
Email works well when you already know something about your audience or can access a list that matches your ideal customer. It’s particularly effective for e-commerce promotions, product launches, event registrations, and lead nurturing, where you’re moving someone from interest toward a specific action. The direct, one-to-one feel of an inbox message tends to drive higher engagement than a banner ad sitting in a sidebar.
If you have an existing subscriber list, promotional emails and automated sequences are the lowest-cost option. If you’re trying to reach new audiences without building a list from scratch, newsletter sponsorships and inbox ads let you borrow someone else’s audience for a fee. Many businesses use both: paid placements to fill the top of the funnel and owned-list emails to convert and retain customers over time.