What is Return on Investment (ROI)?

Return on Investment (ROI) is a simple metric that shows how much profit you earn compared to the money you invested. In digital marketing and business, ROI helps you see which channels, campaigns and projects actually create value.

At its core, Return on Investment (ROI) answers one question: for every euro you put in, how many euros come back out. You calculate ROI with a basic formula that works for both e commerce and B2B.

How to calculate Return on Investment (ROI)

The classic Return on Investment (ROI) formula is straightforward. First you subtract your total costs from your total revenue, then you divide that number by your total costs. Finally, you multiply by 100 to get a percentage.

ROI = (Revenue − Cost) / Cost × 100%

If you invest €10,000 in a performance marketing campaign and generate €30,000 in revenue, your Return on Investment (ROI) is 200 percent. This means you tripled your spend. The same logic applies when you measure ROI on search engine advertising and paid media, SEO, or new tooling.

Why Return on Investment (ROI) matters for growth teams

For growth minded founders and CMOs, Return on Investment (ROI) is the link between marketing activity and business impact. It lets you compare very different bets, like a new landing page versus a sales enablement tool, on the same scale.

  • It shows which channels and campaigns are profitable and which ones waste budget.
  • It helps you prioritise where to scale spend and where to cut back fast.
  • It aligns marketing, sales and finance around clear, shared numbers.
  • It supports better forecasting and predictable growth over time.
  • It exposes vanity metrics, since only real financial outcomes count.

Used consistently, Return on Investment (ROI) becomes a decision filter for every new initiative. If you cannot explain the path to positive ROI, you probably should not launch the project.

Nuances when using Return on Investment (ROI)

Return on Investment (ROI) is powerful, but it is not perfect. In e commerce, you may see fast ROI on campaigns, while in B2B you deal with long sales cycles and multi touch journeys where attribution is messy. Short term ROI can look low even when you are building strong brand and organic demand.

To get a full picture, smart teams combine Return on Investment (ROI) with metrics like customer lifetime value and acquisition cost. In performance marketing this often means zooming out from a single campaign to portfolio level, where the real profit sits. Our guides on performance marketing and growth marketing explain how to do this in more detail.

In practice, the best teams in Belgium and across Europe use Return on Investment (ROI) as a living metric. They track it by channel, by campaign and by segment, then refine their strategy based on what the data shows, not on gut feeling.