The problem with ROAS
ROAS is revenue divided by ad spend. It says nothing about what that revenue cost you to deliver. A 4x ROAS on a product with a 20 percent margin loses money. A 2x ROAS on software with 90 percent margins is excellent. Same dashboard, opposite conclusions.
POAS, profit on ad spend, divides gross profit by ad spend instead. It is the number that tells you whether to scale.
A worked example
| Metric | Product A | Product B |
|---|---|---|
| Ad spend | ₹1,00,000 | ₹1,00,000 |
| Revenue | ₹4,00,000 | ₹4,00,000 |
| ROAS | 4.0x | 4.0x |
| Gross margin | 25% | 65% |
| Gross profit | ₹1,00,000 | ₹2,60,000 |
| POAS | 1.0x | 2.6x |
Product A is breaking even before you have paid a single salary. Product B is funding the business. A ROAS-only dashboard shows them as identical performers, and a media buyer optimising to ROAS will happily scale both.
How to actually implement it
You do not need new software. You need margin data in the conversion value you send back to the ad platform.
- 1Get gross margin per SKU, or per category if per-SKU is unrealistic.
- 2Send profit rather than revenue as the conversion value, using the data layer or a server-side tag.
- 3Set your Target ROAS against profit. Your target number will change, so recalculate it before switching.
- 4Let Smart Bidding run for a few weeks. It is now optimising to something worth optimising to.
If you are lead gen, not e-commerce
The same logic applies with different inputs. Lead value is not uniform. An enquiry for your highest-margin service is worth more than one for your cheapest. Feed differentiated values back from the CRM instead of counting every form fill as one conversion, and the bidding algorithm starts chasing the enquiries you actually want.
Two honest caveats
First, POAS ignores customer lifetime value. On a subscription or repeat-purchase business, a low first-order POAS can be entirely rational. Second, neither metric handles attribution. Both credit the last click and ignore everything that made the customer aware of you.
They are still both better than ROAS alone. If you want help wiring margin data into the ad platforms, that is the measurement half of our performance marketing work.
Frequently asked questions
What is a good POAS?
Above 1.0x you are covering the cost of goods and the ad spend. Whether that is good depends on your fixed costs. Most businesses need considerably more than 1.0x to be genuinely profitable after overheads.
Can I use POAS with Performance Max?
Yes. PMax accepts conversion values like any other campaign type. Send profit instead of revenue and set Target ROAS accordingly.
Is POAS worth it for a small catalogue?
If your margins are similar across products, ROAS is a reasonable proxy and POAS adds little. The wider your margin spread, the more ROAS misleads you.
