Does Email Marketing Still Have the Highest ROI?

Where Does the $36 for Every $1 Email ROI Figure Come From?

The $36-for-$1 email ROI figure traces to surveys of marketers, chiefly Litmus’s State of Email research and, before it, the UK Data & Marketing Association’s Marketer Email Tracker, in which marketers reported what they believe email returns rather than results anyone audited¹.

Litmus sells email testing and analytics software, so this is a vendor surveying its own market, and its current page no longer gives a single average. In its 2025 survey of nearly 500 marketing professionals, 35% said email returns $10 to $36 for every $1 spent, 30% said $36 to $50, and 5% said more than $50¹. The 36:1 figure appears on the same page for software and technology companies, from an older 2020 Litmus survey of more than 2,000 marketers¹. In the 2025 survey, 21% of marketing leaders said they don’t measure email ROI at all, and more respondents judged email’s contribution by engagement such as opens and clicks (59%) than by revenue attributed directly to campaigns (41%)¹.

The DMA’s 2019 tracker put email ROI at a little over £42 for every pound spent, based on what marketers told it, in a year when about two thirds of them said they measured ROI at all². Its public page doesn’t give the sample or the method, and the full report is for members only.

So the fair reading is that marketers who answer email surveys believe their email returns a lot, which is worth knowing, but it isn’t evidence that email will out-earn your other channels if you move money into it.

Why Does Email Marketing Show Such a High ROI?

Email shows a high ROI because the cost side is small, since sending to a list you already own costs little per message, and the return side counts sales from people who already know you, some of whom would have bought anyway.

The cost side usually leaves out what it took to build the list, which was paid for by the ads, events, salespeople and referrals that brought each subscriber in the first place. It often leaves out the people who write, design and manage the emails too. On the return side, the list is mostly customers and warm leads, so when a customer who was about to reorder clicks the link in a newsletter, the email platform records a sale, and the question that matters, which sales you’d have lost without the email, goes unasked. Email platforms grade their own results the same way ad platforms do.

Channels that find new buyers, the subject of the Channel Selection step, carry the full cost of turning a stranger into a customer, so their ROI looks worse on paper even when they’re the channels growing the business. Ranking channels on reported ROI therefore tends to favor the one talking to people you’ve already won.

How Do You Calculate Email Marketing ROI Fairly?

Calculate email ROI with the same method you use for every other channel, then split the result into sales from new customers and sales from existing ones, and test how much of it the email caused. The method itself is in how to measure digital marketing ROI, so this list covers only what changes for email.

1. Count the full cost, including the email platform, the staff time to write, design and manage it, and any money spent buying or growing the list.
2. Split the credited sales by buyer, separating first purchases from people who weren’t yet customers from repeat and expansion sales to existing customers.
3. Use gross profit from your own records, taken from the CRM or order system, rather than the email platform’s revenue report.
4. Hold out a group, sending a campaign to a random part of the list and holding back a comparable part, then comparing what each group buys over the same period, because the difference is what the email caused.
5. Compare channels on new customers won and gross profit, and report email’s sales to existing customers on their own line as retention.

The holdout in step 4 is the only one of these that tells you what email caused, and it costs almost nothing to run, because you already own the list.

Can Email Marketing Replace Channels That Find New Customers?

Email can’t replace the channels that find new buyers, because it only reaches people who have already given you their address, so a company that cuts prospecting to fund more email ends up sending more messages to a list that has stopped growing.

Take a commercial HVAC contractor with annual revenue of about forty million dollars, the running example across these pages, whose most profitable offering is an annual maintenance agreement for commercial buildings. Its pages don’t describe an email program, but its maintenance customers are the kind of audience email serves best.

The same limit applies to leads who haven’t bought yet. Email is a good way to stay in touch with a buyer who asked for something useful and isn’t ready, but how to follow up with sales leads covers why a fresh inbound lead needs a person first, with email as the backup.

Is Email Marketing Worth Investing In?

Email is worth investing in for keeping customers, winning repeat and expansion sales, and following up with leads who aren’t ready to buy, as long as you fund it alongside the channels that bring in new buyers rather than in place of them.

• Give email a retention job, with its own budget line and a target such as repeat purchase rate or renewals, so it isn’t competing with prospecting on reported ROI.
• Run a holdout on your largest regular send before you add budget, and treat the gap between the two groups as email’s real return.
• Write to customers about what they bought, such as service, renewals and the next logical purchase, which is where existing customers are most likely to buy something they wouldn’t have otherwise.
• Keep prospecting funded, and judge it by cost per new customer against the most you can afford to spend to win one, because the list only grows when those channels bring new buyers in.

If you run a smaller business, a plain, regular email to your customer list and one holdout test is enough to learn whether it’s adding sales. If you lead marketing at a larger company, report email’s revenue from existing customers separately from new-customer revenue in the CRM, which the Channel Selection step sets up, so leadership doesn’t move acquisition budget into email on a number that was never comparable.