How to calculate ROI

ROI means return on investment. It shows how much value a business gets back compared to what it spent.

It is often used to evaluate marketing campaigns, software tools, customer journeys, paid media, events, or other business activities. If a company spends money on something, ROI helps answer a simple question: did the result justify the cost?

The basic ROI formula

The most common way to calculate ROI is:

ROI = ((Return - Cost) / Cost) x 100

If a campaign costs €2,000 and generates €10,000 in revenue, the calculation looks like this:

ROI = ((€10,000 - €2,000) / €2,000) x 100

That gives an ROI of 400%.

In plain terms, the campaign generated €4 back for every €1 spent, after covering the original cost.

A simple ROI example

This is a simple example, but the same logic can be used for larger campaigns, new tools, customer communication flows, or sales activities.

What should be included in ROI?

The biggest mistake is only counting the obvious cost.

For a marketing campaign, the cost might not only be ad spend. It could also include creative production, agency support, platform costs, landing page work, internal time, discounts, or campaign management.

The return also needs to be clear. In some cases, it is direct revenue. In others, it may be the value of leads, subscriptions, repeat purchases, renewals, or retained customers.

The more accurate the cost and return figures are, the more useful the ROI calculation becomes.

Why ROI is useful

ROI gives businesses a common way to compare different activities.

A paid campaign, email flow, SMS reminder, event, or software tool may all have different goals and costs. ROI helps show which activities create measurable value and which may need to be adjusted.

It can also help teams make better budget decisions. If one channel consistently creates a stronger return than another, it may deserve more investment. If a campaign has low ROI, the issue may be the audience, offer, timing, channel, landing page, or cost structure.

ROI is not the full story

ROI is useful, but it should not be the only measure of success.

Some activities create value over a longer period. A brand campaign may not generate immediate sales. A customer service improvement may reduce churn later. A marketing automation journey may improve repeat purchases over several months.

That is why ROI should be viewed together with other metrics such as conversion rate, customer lifetime value, retention, acquisition cost, and engagement.

A practical way to calculate ROI

Start by defining what you want to measure. Then decide what counts as return, what counts as cost, and which time period you are measuring.

For example, when measuring a campaign, use the same time period for both revenue and costs. When measuring a tool, include the subscription cost, setup, and the value it helps create. When measuring a customer journey, look at both immediate conversions and later repeat purchases.

ROI works best when it is calculated consistently. The formula is simple, but the quality of the answer depends on the quality of the data behind it.