Marketing ROI measures the net return on your marketing investment. For a profit-based calculation, subtract marketing costs from the incremental contribution generated by marketing, then divide by those marketing costs.
Revenue is not profit. A campaign can report a strong return on ad spend and still lose money after product costs, fulfilment and marketing fees.
Marketing ROI formula
Incremental contribution before marketing = incremental revenue × contribution margin
Marketing ROI = (incremental contribution before marketing − marketing cost)
÷ marketing cost × 100%
Here, contribution margin is the share of revenue left after the variable costs relevant to your decision, before the marketing costs included in the denominator. Avoid subtracting the same cost twice.
Use the same time period and campaign scope for revenue and costs. Include media, creative, agency fees and other marketing costs where they belong to the investment being evaluated. Document allocations when a cost serves several campaigns.
Worked example: 50% marketing ROI
Suppose a controlled test estimates $40,000 of incremental revenue. Your contribution margin before marketing is 60%. Media costs $12,000, and creative and agency costs add $4,000.
| Calculation | Amount |
|---|---|
| Incremental revenue | $40,000 |
| Contribution before marketing: $40,000 × 60% | $24,000 |
| Total marketing cost: $12,000 + $4,000 | $16,000 |
| Contribution after marketing | $8,000 |
| Marketing ROI: $8,000 ÷ $16,000 | 50% |
The investment returned $1.50 of contribution before marketing for each $1 of marketing cost. After recovering that $1, the net return was $0.50. Calling this a 150% ROI would confuse total return with net return.
This is an illustrative point estimate. If the experiment is imprecise, the ROI estimate is imprecise too. Carry the uncertainty into your decision.
ROI vs ROAS vs iROAS vs MER
| Metric | Calculation | What it tells you |
|---|---|---|
| Marketing ROI | Net incremental contribution after marketing ÷ marketing cost | Estimated profitability of the defined investment |
| ROAS | Attributed revenue ÷ ad spend | Revenue credited to advertising under an attribution model |
| iROAS | Incremental revenue ÷ ad spend | Estimated revenue caused by the advertising |
| MER | Total business revenue ÷ defined marketing spend | Blended revenue efficiency, including non-marketing demand |
Always state what is included in the denominator. Teams sometimes use paid media spend for MER and sometimes a broader marketing cost base. Those ratios are not directly comparable.
In the example above, revenue-based iROAS is $40,000 ÷ $12,000 = 3.33x. Marketing ROI is 50%. Both calculations can be correct because they answer different questions. The iROAS guide and free iROAS calculator explain the revenue measure.
A spreadsheet formula for marketing ROI
Put incremental revenue in B2, contribution margin before marketing in B3 and total marketing cost in B4. Use =(B2*B3-B4)/B4 and format the result as a percentage. For the example, enter 40000, 60% and 16000: the result is 50%.
If B4 is zero, ROI is undefined. If B2 is attributed rather than incremental revenue, label that assumption clearly; the formula cannot establish how much revenue marketing caused. For the ad-spend portion, the iROAS calculator compares revenue return with your contribution-margin threshold.
What is a good marketing ROI?
A positive contribution ROI means the estimated incremental contribution covers the marketing costs included in the calculation. It does not automatically cover every company overhead, financing cost or future risk.
Set the threshold against your margin, cash requirements, payback period and the uncertainty of the estimate. There is no universal “good ROI” percentage.
If the denominator is ad spend alone, the revenue-based break-even iROAS is:
Break-even iROAS = 1 ÷ contribution margin before advertising
At 40% margin, that is 2.5x before additional marketing costs. If you include agency or creative costs separately, the required revenue return rises. Keep lifetime revenue and lifetime costs on a consistent basis rather than comparing projected lifetime revenue with an incomplete cost total.
How to estimate incremental revenue
Use a well-designed holdout or geo experiment to estimate what would have happened without the advertising. At broader scale, MMM can inform channel contribution under its modeling assumptions.
Platform-attributed revenue alone cannot establish incremental revenue. Adding revenue claims across platforms may also count the same sale more than once. MER can help you monitor overall business trends, but a change in MER does not prove that marketing caused the change.