Revenue must also pay delivery costs. At 40% contribution margin, 2.5 times ad spend is needed just to fund that spend.
Try this with your own numbersFormula and worked example
Break-even ROAS = 1 / contribution margin
| Input | Example |
|---|---|
| Contribution margin before advertising | 40 % |
| Calculated result | 2.5 × revenue / ad spend |
Choose reliable inputs
Allow time for preparation, the service itself and cleaning up before the next appointment. For this dental practice calculation, use appointment history, service durations and supply costs and a consistent definition of one appointment.
- Clinical labour: include the portion belonging to this appointment or reporting period, and record where the value came from.
- Supplies: include the portion belonging to this appointment or reporting period, and record where the value came from.
- Room overhead: include the portion belonging to this appointment or reporting period, and record where the value came from.
Use the same currency for every money input. Do not mix weekly costs with monthly revenue, or count the same expense in both an itemised cost and allocated overhead.
Why is a ROAS above one sometimes unprofitable?
Revenue must also pay delivery costs. At 40% contribution margin, 2.5 times ad spend is needed just to fund that spend.
Assumes attributable sales and a stable contribution margin; fixed costs are excluded.
What if this input changes?
If contribution margin before advertising rises by 10%, this example changes by -0.2273 × revenue / ad spend. This shows the effect of one change; it does not predict what will happen.
Open the calculator, save your baseline, then change the input supported by the least reliable estimate in your records. Compare both scenarios before committing to a price or capacity promise.