ROAS, ROI and margin

If you have sat in a marketing meeting, you have probably heard ROAS, ROI and margin used as if they meant the same thing. They don’t. Mixing them up is one of the quickest ways to lose credibility with a finance team, and one of the easiest mistakes to fix.

The trick is to remember that each number answers a different question:

Let’s take them one at a time, using the same example throughout.

▸ Example — The example. An online shop spends $5,000 on ads in a month. The ads bring in $20,000 of revenue. The products sold cost the shop $12,000 to buy and ship. A freelancer charged $1,000 to run the campaign. Illustrative numbers.

ROAS: a revenue ratio

▸ Definition — ROAS (return on ad spend): revenue attributed to ads ÷ money spent on those ads. Usually written as a ratio (4.0) or a percentage (400%).

In our example, ROAS = $20,000 ÷ $5,000 = 4.0. Every ad dollar brought back four dollars of revenue.

ROAS is popular because it’s fast. The ad platforms calculate it for you, it updates daily and it’s handy for comparing campaigns against each other. Its weakness is that it knows nothing about costs other than ad spend. A ROAS of 4 looks the same whether you sell diamonds or bottled water.

Margin: how much of each sale you keep

▸ Definition — Gross margin: the share of revenue left after the cost of the goods sold. Often called simply “margin” in marketing conversations.

In our example, gross margin = ($20,000 − $12,000) ÷ $20,000 = 40%. For every dollar of sales, the shop keeps 40 cents before paying for marketing, staff, rent and everything else.

Margin isn’t a marketing metric. It belongs to the product and the price. But it decides what every marketing metric means. That’s why the best marketers know the margin on their main products by heart.

ROI: did the whole thing make money?

▸ Definition — ROI (return on investment): the profit an investment produced, minus what it cost, divided by what it cost. Shown as a percentage.

This is the number a finance director actually wants. Let’s work it through:

1. Gross profit from the sales: $20,000 × 40% = $8,000
2. Total cost of the campaign: $5,000 ads + $1,000 freelancer = $6,000
3. ROI = ($8,000 − $6,000) ÷ $6,000 = 33%

So the campaign returned 33 cents of profit for every dollar invested. A ROAS of 4.0 and an ROI of 33% describe the same month. They just answer different questions.

▸ Margin note — Some companies calculate marketing ROI on revenue rather than profit. If someone quotes an ROI, it’s always fair to ask: “Is that on revenue or on profit?” The answer can change the number several times over.

How the three fit together

A useful analogy is a car journey. ROAS is your speed: easy to read, updated constantly, good for moment-to-moment decisions. Margin is your fuel efficiency: it’s set by the car, not by how you drive, but it decides how far you can go. ROI is whether the trip was worth taking at all, worked out when you arrive.

In practice:

• Use ROAS day to day, to compare campaigns, ad sets and keywords against a target.
• Use margin to set that ROAS target. Break-even ROAS is 1 ÷ margin. At 40% margin, that’s 2.5.
• Use ROI to judge whether a whole campaign, channel or quarter was worth it, including every cost.

Break-even ROAS = 1 ÷ gross margin

At a 40% margin, any ROAS below 2.5 loses money before overheads.

Take it to work

You now know more about these three numbers than many people who use them every day. Use that carefully, and kindly, in meetings.