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ROI (return on investment): definition

Analytics

By Alvyn Detavernier, founder · published October 28, 2026

Definition

ROI (return on investment) measures how much an investment earns compared with what it cost. The formula is (net gain minus cost) divided by cost, times 100. An ROI of 150% means every dollar invested was paid back and generated $1.50 in profit on top, which makes ROI the standard way to compare very different marketing spends.

Also known as: ROI, return on investment, marketing ROI

The ROI formula

ROI = (gain - cost) / cost × 100. In marketing, "gain" should be gross profit, not revenue. A $1,000 sale at a 30% gross margin only brings in $300 to cover what you spent.

An ROI of 0% means you broke even. A negative ROI is a loss: -40% means every $100 spent returned only $60 in profit.

Pair ROI with the payback period, the number of months before cumulative profit covers the cost. Two campaigns can both show a 60% ROI, yet the one that pays back in two months frees up cash far sooner than the one that needs ten.

ROI vs. ROAS

ROAS (return on ad spend) divides revenue by ad spend alone. It is handy for day-to-day campaign management, but it ignores margin, fees and overhead. A 4:1 ROAS can hide a losing campaign if your margin is 20%.

Your break-even ROAS is 1 divided by your margin. At a 25% margin you need at least $4 in sales per $1 of ads just to break even on media, before agency fees or software.

Costs to include

An honest ROI counts every cost tied to the activity:

media spend (clicks, impressions, sponsored placements);
agency or freelancer fees, plus the value of in-house time;
software such as CRM, call tracking and email tools;
creative production: photos, video, copywriting;
for a website: design, development, hosting and maintenance over its useful life.

Common mistakes

Using revenue instead of profit. Judging too early: SEO and a new website pay back over 12 to 36 months, not one quarter. Ignoring customer lifetime value when clients buy again every year. Giving the last click all the credit, which inflates branded search ROI and undervalues prospecting campaigns that started the journey.

Example

Example: an HVAC company spends $2,500 on a campaign ($2,000 in clicks plus $500 in management) and books $10,000 in installs at a 40% gross margin, or $4,000 in profit. ROI = ($4,000 - $2,500) / $2,500 = 60%, while Google Ads reports a 5:1 ROAS ($10,000 / $2,000).

Frequently asked questions.

What is a good marketing ROI?

Any positive ROI calculated on profit and total cost means the activity earns more than it costs. Beyond that, a good number depends on your cash flow and alternatives: 30% in three months is strong for a paid campaign, while a website or SEO program should be judged over several years.

How do I calculate the ROI of a website?

Add design, development, hosting and maintenance over three years, then estimate the profit from customers the site brought in: tracked calls, form leads matched in your CRM and online sales. For example, $9,000 in total cost and 40 customers at $600 profit each gives $24,000, an ROI of about 167%.

Should I stop a campaign with negative ROI?

Not immediately. First check conversion tracking, your sales cycle (a deal that closes in 90 days will not show up yet) and repeat purchases. If ROI is still negative after that, cut the least profitable keywords, audiences and placements before shutting the whole campaign down.

Related terms.

The concepts that go with it, to round out the definition.

Analytics

Customer lifetime value (LTV)

Customer lifetime value (LTV) is the revenue or gross profit a customer generates on average over their entire relationship with a business. It tells...

Analytics

Customer acquisition cost (CAC)

Customer acquisition cost (CAC) is the average total cost of winning one new paying customer. It adds up ad spend, marketing and sales salaries,...

Paid advertising

CPA (cost per acquisition)

CPA (cost per acquisition) is the average amount of ad spend needed to generate one conversion, such as a sale, a quote request, a booked call or a...

Put it into practice.

Free tool

ROAS Calculator

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