Key takeaways
ROI (return on investment) is calculated by comparing the revenue generated by a marketing action to its total cost, including the time spent
Measuring your digital ROI requires reliable tracking: without correct data, all calculations are skewed
Each lever (SEO, SEA, email, social networks) has its own indicators and its own profitability horizon
The goal is not to have the highest ROI on a single lever, but to manage all your actions to maximise overall profitability
A simple dashboard, updated monthly, is sufficient to effectively manage your digital performance
"We have been investing in digital for two years, but I don't really know if it pays off." We hear this phrase regularly. It reflects a common reality : many companies spend on digital marketing without having a clear method to evaluate the return. Some over-invest in low-return levers. Others under-invest in channels that work well, due to the inability to demonstrate it with supporting figures.
Measuring the ROI of your digital marketing actions is precisely what allows you to make informed decisions. Here’s how to proceed, step by step.
What is ROI and how is it calculated ?
ROI, or Return On Investment (return on investment), is a ratio that expresses the profit generated in relation to what an action has cost you. The basic formula is simple :
ROI = (Revenue generated − Cost of the action) ÷ Cost of the action × 100
A ROI of 200% means that for every 1 euro invested, you have recovered 3 (your initial stake plus 2 euros of profit). A negative ROI means that the action cost more than it generated.
However, be careful not to reduce the cost of a marketing action to its direct cost alone. If you manage your Google Ads campaigns yourself, the time you spend on it has a value. If you outsource to an agency, the fees are part of the calculation. A Google Ads campaign that generates 5,000 euros in revenue for 1,500 euros in media investment and 800 euros in agency fees shows a ROI of 112% — and not 233% if the fees are ignored.
Step 1 : Define your objectives and conversions
Before measuring anything, you need to define what you consider to be a result. In digital marketing, this is called a conversion. Depending on your business, a conversion can be an online purchase, a request for a quote, a phone call, a document download, a newsletter sign-up, or an appointment booking.
Without a clear objective, it is impossible to measure. Worse still: you risk drowning in data that has no business meaning. The number of "likes" on a LinkedIn post is not a conversion. Traffic to your site is not a conversion. What matters is the action that brings you closer to a sale.
For each digital channel you use, ask yourself this question : what action do I want my visitor to take? It is this action that must be tracked, measured, and valued.
Step 2 : Set up reliable tracking
This is the most technical step, but also the most critical. A tracking system that is poorly configured produces inaccurate data, and inaccurate data leads to poor decisions.
The fundamental tools to implement are Google Analytics 4, which measures visitor behaviour on your site, and Google Tag Manager, which allows you to deploy and manage your tracking tags without touching your site's code. In addition, there is the Meta pixel if you are advertising on Facebook and Instagram, and the Google Ads conversion tags if you are using that channel.
One often overlooked point is consent management. Since the implementation of GDPR, users can refuse measurement cookies. If your consent banner is poorly configured and generates a low acceptance rate, your GA4 data reflects only part of the reality. Optimising your CMP (Consent Management Platform) to improve the acceptance rate is therefore an essential prerequisite for reliable measurement.
Step 3 : Calculate ROI by lever
Once tracking is in place, you can calculate the ROI of each lever separately. It is important to understand that each channel has a different profitability horizon.
Lever | Profitability horizon | What we measure |
|---|---|---|
Google Ads (Search) | Immediate | ROAS, cost per conversion, CPA |
Meta Ads | Short term (1-4 weeks) | Cost per lead, ROAS, qualified reach |
SEO / Content | Medium-long term (3-12 months) | Organic traffic, leads generated, cost per SEO lead |
Email marketing | Short term | Email conversion rate, revenue per email sent |
Social media (organic) | Long term | Indirect leads, brand awareness, engagement rate |
For Google Ads, ROAS (Return On Ad Spend) is the preferred indicator. It is calculated as follows: revenue generated ÷ advertising expenses. A ROAS of 4 means that every euro spent on advertising has returned 4.
For SEO, the approach is different because there isno direct expense per click. We calculate the total cost (writing, technical optimisation, link building, time spent) and it is compared to the revenue generated by organic traffic over a given period. The horizon is longer, but the cost per acquisition generally decreases over time, unlike paid advertising.
Step 4 : Correctly attribute conversions
One of the challenges of digital marketing is that the customer journey rarely goes through a single channel. A prospect may discover your business through a blog post (SEO), find you again a few days later through a retargeting ad,(SEA), and then finally contact you after seeing a LinkedIn post. Which action should receive credit for this conversion?(SEA), puis finalement vous contacter après avoir vu une publication LinkedIn. Quelle action doit recevoir le crédit de cette conversion ?
This is known as the attribution problem. Google Analytics 4 offers several attribution models : last click (all credit goes to the last channel before conversion), first click (all credit goes to the discovery channel), or the data-driven model, which distributes credit among all touchpoints.
For informed marketing decisions, the data-driven model is the most relevant, but it requires a sufficient volume of conversions to work. For businesses with a modest volume of conversions, the linear model — which evenly distributes credit among all touched channels — is a good practical alternative.
Step 5 : Build a monthly dashboard
Measuring ROI is only valuable if it is regular. A monthly dashboard, however simple it may be, allows you to track the evolution of your indicators, identify trends, and make informed budget allocation decisions.
A good dashboard for managing your digital ROI should include, for each active lever: the total cost (media investment + fees), the number of conversions generated, the cost per conversion, and the revenue or attributable income. Looker Studio(formerly Google Data Studio) is a free tool that allows you to create these dashboards visually, by directly connecting your data sources (GA4, Google Ads, etc.).
The aim of this tracking is not to find the perfect lever, but to understand how your channels work together and where to focus your efforts to maximise your overall profitability.
Measuring the ROI of your digital marketing actions requires initial organisation — defining your objectives, setting up a reliable tracking, structuring your reporting— but this organisation pays off quickly. It allows you to move out of the fog, defend your investments with concrete figures, and above all, make decisions based on reality rather than intuition. In an environment where budgets are tight and results are expected, this is a considerable competitive advantage.
FAQ
Can we measure the ROI of SEO when we do not pay per click? Yes, absolutely. SEO has a cost: content writing, technical optimisations, and possibly agency services. We calculate this total cost over a period, add it up, and compare it to the revenue generated by organic traffic during the same period. The ROI of SEO is often very high in the long term, as the cost per acquisition decreases as the content ranks.
What minimum ROI should we aim for in a Google Ads campaign? There is no universal rule, as it depends on your margin and your acceptable acquisition cost. Generally speaking, a ROAS of 3 to 4 (which is an ROI of 200 to 300%) is considered healthy for an e-commerce campaign. For lead generation, the cost per lead should remain below the average value of a customer divided by your sales closing rate.
My tracking is in place, but my data does not seem consistent. What should I do? Start by checking your cookie consent rate: if less than 50% of your visitors accept it, your data is likely to be significantly underestimated. Next, ensure that your conversion events are well defined and that tag duplicates are excluded via Google Tag Manager. A tracking audit is often the first recommended step.
Do organic social media have a measurable ROI? Directly, it is difficult. Organic social media mainly contribute to brand awareness and trust, effects that are measured indirectly through the evolution of direct traffic, branded search (searches for your name on Google), and conversion rates on other channels. They should not be evaluated as a direct acquisition channel, but as an investment in customer relationships.
How often should one analyse their digital ROI? A monthly review is the minimum recommended frequency for SMEs and micro-enterprises. For active advertising accounts (Google Ads, Meta Ads), a weekly analysis of key indicators allows for real-time campaign optimisation. Quarterly analysis serves to take a step back and adjust strategic directions.