ROAS vs MoAS: why margin on ad spend is the number your agency should report

Every agency reports ROAS. Almost none report the number that actually tells a client whether their marketing made money. That number is MoAS - margin on ad spend - and the gap between the two is where profit quietly disappears.

What ROAS actually measures

ROAS (return on ad spend) is revenue divided by ad spend. A 4x ROAS means every $1 spent on ads brought back $4 in revenue. It's the default agency metric because it's easy to pull from any ad platform and easy to explain in a client meeting.

But revenue is not profit. A product with a 20% gross margin at 4x ROAS is a completely different business from a product with a 70% margin at the same 4x. ROAS cannot see the difference - it stops at the top line, before the cost of the product, shipping, and payment fees ever enter the picture.

What MoAS measures

MoAS (margin on ad spend) is gross profit divided by ad spend. It answers the question the client is actually asking: for every dollar we put into ads, how many dollars of profit came back?

Take the same 4x ROAS campaign and change only the margin:

• 70% margin: $4 revenue produces $2.80 of gross profit, so MoAS is 2.8x - healthy.
• 20% margin: $4 revenue produces $0.80 of gross profit, so MoAS is 0.8x - losing money after ad spend.

Same ROAS. One client is scaling profitably; the other is buying revenue at a loss. If you only report ROAS, you cannot tell them apart - and you will keep recommending "scale it" on campaigns that are quietly draining the account.

Why this matters more for an agency

When you manage one brand, you eventually learn its margins by feel. When you manage ten, you cannot. Each client has different products, different costs, and different break-even points, and the platform ROAS looks reassuringly similar across all of them.

That is exactly the trap. The dashboards say every account is "performing," the client's bank balance says otherwise, and you are the one who gets the hard question on the quarterly call. Reporting MoAS is how you get ahead of that question instead of being cornered by it.

How to report it

You do not need a data team to do this well:

1. Get the margin. Ask each client for their gross margin, or the COGS, shipping, and payment-fee percentages. One number per product line is enough to start.
2. Compute MoAS per campaign, not just per account. The account average hides the losing campaigns inside the winning ones.
3. Rank and flag. Show the client a ranked list of campaigns by MoAS, and flag anything below 1.0x - that is money lost after ad spend, before you have even counted overhead.
4. Recommend on MoAS, not ROAS. "Scale the 3.2x MoAS campaign, cut the 0.7x one" is a recommendation a client can act on and trust. "Scale the high-ROAS campaign" is how accounts lose money.

The one-line version

Report ROAS to show activity. Report MoAS to show whether the client actually made money. The second is the one that keeps the account.

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Addlaa computes MoAS and net profit for every client automatically - alongside ROAS - so your team reports on profit, not just revenue, without building a spreadsheet. See it on sample data, no signup required.