How to calculate ROAS (and why yours is probably overstated)

Return on ad spend looks like the easiest metric in marketing: revenue divided by spend. The arithmetic is trivial. Getting it honest is the hard part — because both the “revenue” and the “spend” in that fraction are usually missing pieces, and the missing pieces always tilt the number in your favor.

The formula, two ways

There isn’t one ROAS. There are at least two, and they answer different questions. Platform ROAS grades a channel. Blended ROAS grades the business.

-- platform ROAS (what the ad account shows you)
ROAS = attributed_conversion_value / ad_spend

-- blended ROAS (what your finance team believes)
blended_ROAS = total_revenue / total_marketing_cost

Watch a “4x” become a 2.9x

The same campaign can look like a triumph or a coin-flip depending on which costs you let into the denominator. Load in the spend the ad platform never sees and the story changes:

Platform ROAS is a marketing metric. Blended ROAS is a business metric. Only one of them survives a meeting with finance.

Why the platform number runs hot

The costs you’re probably leaving out

• Agency or in-house management time
• Creative production and editing
• Martech and analytics tooling
• Discounts, refunds, and returns booked against that revenue
• Cost of goods, if you want true profit rather than a vanity multiple

A sanity check before it goes on a slide

1. 1State exactly which costs are in the denominator — media-only or fully loaded.
2. 2Use one attribution window, consistently, across every channel.
3. 3Reconcile revenue to the CRM or finance system, not the pixel.
4. 4Separate new-customer revenue from repeat orders.
5. 5Always show blended ROAS next to platform ROAS — never platform alone.

None of this shrinks ROAS for sport. It makes the number true — and a true number you can defend beats a flattering one you can’t every time you’re asked “where did that come from?” Maven blends media cost, fees, and reconciled revenue into one ROAS you can stand behind; book a demo to see it on your numbers.