LESSON 9 OF 13
How to set an ad budget from a profit target, not a gut feel
Why the budget and the ROAS it needs are not independent numbers.
Most operators set their ad budget based on what feels comfortable to spend, or comfortable to lose. It is an emotional response to risking capital without knowing how it needs to perform. An ad budget with no mathematical framework behind it feels like gambling because it is gambling.
The correct way to think about ad budget is as a function of the contribution margin being produced by revenue, set against fixed expenses. That is the space that answers the two questions that matter: how much do we need to spend, and how does it need to perform?
Required ROAS moves with budget
The return on ad spend a business needs in order to hit a given profit target changes as the ad budget changes — and it moves in the direction most people do not expect. As ad budget goes up, the ROAS required to break even comes down. The relationship follows a curve; the shape matters more than its name.
| Ad budget | ROAS needed to break even |
|---|---|
| $10,000 | 22 |
| $50,000 | 6 |
| $100,000 | 4 |
A 22 ROAS is not going to happen. Recognising that is the point of the exercise: at $10,000 of budget, that business is set up to fail no matter how good the marketing is. At $100,000 it needs a 4, which is a real number a competent team can chase.
Do not operate at the extremes
You cannot juice ad spend to infinity to drive required ROAS as low as possible — that is unrealistic. And a tiny budget can demand a return of 25, which is equally unrealistic. There is a middle space, and understanding it is what makes the decision produce a realistic outcome.
This is why budget cannot be viewed purely as a cost line. It is the fuel for the engine: the more you put in, the faster the engine runs, and the less efficient it has to be to produce the outcome you are chasing.