2015: $36 for Every $1: How Email Became Marketing's Best Investment

There’s a number that email marketers recite like scripture: $36. As in, for every $1 spent on email marketing, the average return is $36. Some studies put it higher — the Data & Marketing Association (DMA) has reported figures as high as $42. Others are more conservative. But even the lowest credible estimates place email marketing’s return on investment far above any other digital marketing channel.

This isn’t a new phenomenon, but it wasn’t always recognized. For years, email marketing was treated as the boring workhorse of digital marketing — reliable but unsexy, always there but never the center of attention. Social media, paid search, influencer marketing, and whatever the latest shiny object happened to be all commanded more conference keynotes and bigger budgets. Yet year after year, when companies actually measured returns, email kept winning.

Why the Numbers Are So Good

Email’s extraordinary ROI comes from a combination of low costs and high returns, both of which are structural advantages of the channel.

The cost side is almost negligible. Sending an email costs fractions of a cent. Even using a premium email marketing platform with all the bells and whistles — automation, segmentation, A/B testing, analytics — the cost per message typically falls between $0.001 and $0.01. A company with a 100,000-subscriber list might pay $500-$1,500 per month for its email platform. If those subscribers generate even modest revenue, the math is overwhelmingly favorable.

Compare this to paid advertising, where you’re paying for each click or impression. A single Google Ads click in a competitive industry can cost $5, $10, or even $50. A Facebook ad campaign reaching 100,000 people might cost $2,000-$5,000 — and there’s no guarantee those people want to hear from you.

The audience is pre-qualified. This is email’s most underappreciated structural advantage. Email subscribers opted in. They gave you their address because they wanted to hear from you. This is fundamentally different from social media followers (who may never see your posts due to algorithms), search ad recipients (who are clicking on an ad while looking for something else), or display ad viewers (who are mostly ignoring the ad entirely).

An opt-in audience has higher open rates, higher click rates, and higher conversion rates than any audience you can rent or buy. The difference is not marginal — it’s often an order of magnitude.

Direct delivery, no intermediary. When you send an email, it arrives in the recipient’s inbox. No algorithm decides whether they see it. No platform takes a cut. No competitor can outbid you for placement. The directness of email delivery is unique among digital marketing channels and becomes more valuable as social media algorithms become more opaque.

The Evidence

The $36:$1 figure isn’t based on one study or one company’s data. It’s a consistent finding across multiple research sources over many years:

The DMA (now the Data & Marketing Association, part of the Association of National Advertisers) has tracked email marketing ROI since the mid-2000s. Their annual reports consistently place email at or near the top of all marketing channels, with ROI figures ranging from $35 to $44 per dollar spent.

Litmus, the email testing and analytics platform, published a widely cited 2019 study finding a median email marketing ROI of $36:$1, based on a survey of over 400 marketers across multiple industries. Their subsequent studies have found similar or higher figures.

Campaign Monitor, Mailchimp, and other email platform providers have published their own analyses showing comparable results, though these should be read with the understanding that email marketing companies have an interest in promoting email marketing.

The figures vary by industry. E-commerce and retail tend to see the highest email ROI because email drives direct purchases. B2B companies see strong but lower ROI because sales cycles are longer and attribution is more complex. But across virtually every industry measured, email outperforms other channels.

What Changed in 2015

While email marketing has always been cost-effective, the mid-2010s represented a turning point in industry recognition. Several factors converged around 2015 to elevate email from “that thing we do because we’ve always done it” to “our most important marketing channel”:

Social media reach collapsed. Facebook’s organic reach for brand pages dropped from an estimated 16% in 2012 to approximately 2-3% by 2015. Brands that had invested heavily in building Facebook followings discovered that those followers were essentially locked behind a paywall. Email lists, by contrast, remained accessible.

Marketing automation matured. Platforms like HubSpot, Marketo, ActiveCampaign, and Mailchimp’s automation features made it possible to send triggered, personalized email sequences without manual intervention. Welcome series, abandoned cart emails, re-engagement campaigns — these automated workflows generated revenue around the clock with minimal ongoing effort.

Measurement got better. Improved attribution tools allowed marketers to more accurately connect email campaigns to revenue. As measurement improved, email’s contribution became harder to ignore. Many companies discovered that email was already their top revenue channel — they just hadn’t been measuring it properly.

Mobile email exploded. By 2015, more email was opened on mobile devices than on desktop. This wasn’t a problem — it was an opportunity. People now checked email constantly, throughout the day, wherever they were. The window for reaching customers expanded from “when they’re at their desk” to “every waking hour.”

The Compounding Effect

Email’s ROI isn’t just about individual campaigns. It’s about the compounding effect of a growing, engaged subscriber list. Unlike paid advertising, where each new campaign starts from zero, an email list is a cumulative asset. Each new subscriber increases the potential revenue from every future email sent.

A company that builds a 50,000-subscriber list over five years has a marketing asset that generates returns without additional acquisition costs. Compare this to paid advertising, where the cost of reaching each person must be paid each time. Email is an investment that pays dividends indefinitely.

This compounding effect is why experienced marketers treat email list growth as a strategic priority rather than a tactical afterthought. The list is the asset. The emails are how the asset generates returns.

The Bottom Line

Email marketing’s $36:$1 ROI isn’t magic. It’s the predictable result of extremely low costs, a pre-qualified audience, direct delivery, and a compounding subscriber base. The channel doesn’t require creative genius or a massive budget. It requires consistency, relevance, and respect for the subscriber’s attention.

Curious what your own email program could generate? Our ROI Calculator lets you plug in your actual numbers — list size, open rate, conversion rate — and see exactly what your email investment is worth.

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Frequently Asked Questions

What is the ROI of email marketing?

According to multiple industry studies, email marketing returns an average of $36-$42 for every $1 spent. The exact figure varies by study and industry, but email consistently outperforms all other digital marketing channels in ROI.

Why is email marketing ROI so high?

Email marketing costs are very low (pennies per message), the audience is opt-in (higher engagement), messages go directly to subscribers without algorithmic filtering, and the channel supports personalization, segmentation, and automation — all of which drive conversions.

How does email marketing ROI compare to other channels?

Email's $36:$1 ROI significantly exceeds social media marketing (typically $2-$5 per $1), paid search ($2-$8 per $1), and display advertising ($1-$3 per $1). Only SEO approaches comparable long-term ROI, though it requires larger upfront investment.