Marketing ROI: Formula, Worked Examples, ROAS vs ROMI and ROI by Channel

Marketing ROI is the number finance asks for and marketing struggles to give. The formula is simple; the difficulty lies in deciding which revenue comes from which action, over which period, and whether that revenue would have happened anyway. Marketing budgets stayed almost flat at 7.8% of company revenue in 2026, according to Gartner's annual CMO Spend Survey (401 marketing leaders surveyed from January to March 2026), so every channel has to justify its share. This guide gives the formulas, worked examples, the differences between ROI, ROAS and ROMI, and how to read ROI channel by channel.

What is marketing ROI?

Marketing ROI (return on investment) is the ratio between the profit generated by a marketing action and its cost. A ROI of 200% means that each $1 spent brought back $2 of profit on top of the $1 recovered. A ROI of 0% means the action paid for itself and nothing more; a negative ROI means it lost money.

Marketing ROI is used for three decisions: whether to keep an action, how to split the budget between channels, and how much to invest next year. Our guide to the marketing budget covers the third question in detail.

How do you calculate marketing ROI?

The simple formula (on revenue)

Marketing ROI = (attributed revenue − marketing cost) ÷ marketing cost × 100

It is quick but misleading: it treats all revenue as profit, while the business still has to pay for the products, delivery and support behind that revenue.

The reliable formula (on gross margin)

Marketing ROI = (attributed revenue × gross margin rate − marketing cost) ÷ marketing cost × 100

This is the version to present to finance. It matches the definition of return on marketing investment given by Wikipedia's ROMI article: contribution to profit attributable to marketing, net of marketing spending, divided by the marketing spending.

Worked example (fictitious figures)

An online store spends $10,000 on a campaign (media, creation and tools included) and attributes $40,000 of sales to it. Its gross margin is 50%.

The same campaign shows 300% or 100% depending on the formula. With a 50% margin, any ROAS below 2 loses money even though it looks positive. Our free ROAS calculator gives the break-even point for your own margin.

What costs should you include?

Count everything the action requires: media spend, agency or freelance fees, software, production (visuals, video, writing) and the internal time spent on it. Leaving out salaries and tools is the most common way to inflate a ROI. For organic channels, where there is little or no media spend, these costs are almost the whole investment.

What is the difference between ROI, ROAS and ROMI?

ROAS ignores margin and every cost other than media. Google Ads defines it as conversion value divided by ad spend: in its help article on target ROAS bidding, $5 in sales for $1 in ad spend equals a 500% target ROAS. A high ROAS can hide a negative ROI if margins are thin; ROAS is a steering metric for performance marketing, ROI and ROMI are business metrics.

How does ROI differ by marketing channel?

Channels do not pay back on the same timeline or with the same cost structure, so comparing their ROI over one month favors the fastest ones.

For organic channels, measure ROI over 12 to 24 months and include the traffic that existing pages keep bringing. Our free SEO ROI calculator and content marketing ROI calculator project returns over time rather than on one month. The indicators to follow along the way are listed in our guide to SEO KPIs.

Why is marketing ROI hard to measure?

Attribution

A customer often sees an ad, reads an article, receives an email and then buys. Which action gets the credit? The answer depends on the marketing attribution model. Google Analytics 4 now offers only data-driven attribution and last-click variants: Google's attribution documentation states that the first click, linear, time decay and position-based models have not been available since November 2023. Last click favors the channels that close sales (branded search, email) at the expense of those that create demand (content, social, video).

Incrementality

The real question is what would have happened without the action. Retargeting ads and branded search campaigns often take credit for customers who were going to buy anyway. Holdout tests (a group that does not see the campaign) and before/after comparisons by region measure the real uplift. At the scale of the whole budget, marketing mix modeling estimates the contribution of each channel from historical data.

Customer value over time

A first purchase rarely tells the whole story. A campaign that brings customers who reorder for years is worth more than one that brings one-time buyers at the same cost. Calculating ROI on customer lifetime value rather than on the first order changes the ranking of channels; our customer lifetime value calculator gives that figure.

How do you improve marketing ROI?

1. Cut what does not pay back: rank campaigns by ROI on margin and stop the bottom tenth each quarter.
2. Improve conversion before buying more traffic: a landing page that converts 3% instead of 2% raises the ROI of every channel that feeds it.
3. Shift budget toward assets that accumulate: an article that ranks keeps bringing visits without new spending, unlike an ad.
4. Raise customer value: onboarding emails, cross-selling and retention make each acquired customer worth more.
5. Test incrementality on the largest lines: pausing a campaign in one region for a few weeks often reveals sales it was only claiming.

What is the ROI of visibility in AI answers?

ChatGPT, Gemini and Perplexity now answer purchase questions directly, often citing a few brands and sources. Being cited there has a value that classic ROI tracking misses: many of these answers send no click, and the visits they do send are hidden in generic referral traffic.

Three measurements give a usable estimate:

1. AI-referred visits and conversions, isolated in GA4 with a channel group for AI domains (see our guide to building a marketing dashboard).
2. Mention and citation rate of your brand on a fixed list of buyer questions, compared with competitors, measured with AI mention tracking.
3. The value of a missed citation: what a competitor gains each time an assistant recommends it instead of you. Our GEO ROI calculator turns these inputs into an estimated return.

The investment side is mostly content: pages that answer buyer questions clearly, with sources and data. Sorank's blog article generator writes and publishes those articles for Google and AI on your site, with plans from $49 a month billed yearly on the pricing page, which keeps the cost side of the ROI fixed and known.

A ROI figure finance can trust

A credible marketing ROI uses gross margin, counts every cost, states its attribution model and fits the time window to the channel. Compare channels on margin, over their real payback period, and test incrementality on the biggest budgets: that is what turns ROI from a defensive number into a tool for moving money to what works. Start with your three largest budget lines this quarter.