Growth economics
Google Ads ROAS forecast: estimate return and profit before you spend
Run the forecast with at least three cases. One number hides how much a small change in cost per click or conversion rate moves the result.
The direct answer
To forecast Google Ads ROAS, divide budget by cost per click to get clicks. Multiply clicks by conversion rate to get orders. Multiply orders by average order value to get revenue. Divide revenue by spend. Then apply gross margin to see profit. A forecast is only as good as its inputs, so test it with a low and a high case before you commit budget.
1. Turn budget into orders and revenue
Start with the monthly budget and your expected cost per click. Divide one by the other to get clicks. Apply your conversion rate to get orders. Multiply by average order value to get revenue.
Use figures from your own account or store where you can. A new account has no history. In that case mark each input as an assumption and plan to replace it with real data within the first weeks.
- Clicks = budget / cost per click.
- Orders = clicks x conversion rate.
- Revenue = orders x average order value.
- ROAS = revenue / ad spend.
- Gross profit = revenue x gross margin.
2. Follow one example from budget to profit
The numbers are invented to show the steps. They are not a benchmark, a client result, or a promise.
| Item | Amount |
|---|---|
| Monthly budget | $40,000 |
| Cost per click | $4 |
| Clicks (40,000 / 4) | 10,000 |
| Conversion rate | 4% |
| Orders (10,000 x 0.04) | 400 |
| Average order value | $120 |
| Revenue (400 x 120) | $48,000 |
| ROAS (48,000 / 40,000) | 1.2x |
| Gross margin (assumed) | 60% |
| Gross profit (48,000 x 0.60) | $28,800 |
| Result after ad spend (28,800 - 40,000) | -$11,200 |
3. Test a low case and a high case
A single forecast looks precise but is not. Change one input at a time and see how far the result moves. In this example, a small rise in cost per click or a small fall in conversion rate pushes ROAS below 1.0x.
This is why the forecast helps you set limits. It shows how much slack your plan has before the numbers stop working.
| Case | Change | Orders | Revenue | ROAS |
|---|---|---|---|---|
| Base | None | 400 | $48,000 | 1.2x |
| Higher cost per click | $5 instead of $4 | 320 | $38,400 | 0.96x |
| Lower conversion rate | 3% instead of 4% | 300 | $36,000 | 0.9x |
| Higher order value | $150 instead of $120 | 400 | $60,000 | 1.5x |
4. Add repeat orders before you judge the first month
A first-order forecast ignores customers who buy again. If your customers do come back, the real return is higher than the first-order ROAS. That can change whether the plan is worth running.
Use real repeat data from your store. The example below assumes each customer places 2.5 orders in total over the window. That figure is invented to show the method. Replace it with your own.
| Item | First order only | With 2.5 orders per customer |
|---|---|---|
| Customers won | 400 | 400 |
| Revenue | $48,000 | $120,000 |
| Return on ad spend | 1.2x | 3.0x |
| Gross profit at 60% | $28,800 | $72,000 |
| Result after $40,000 spend | -$11,200 | +$32,000 |
5. Know what the forecast cannot tell you
A forecast does not know your competitors, your season, or how fast your product sells. It also assumes cost per click and conversion rate stay steady as you add spend. In practice they often move.
Treat the result as a planning range. Compare it with the break-even ROAS your margin needs. Then review real results against it each month.
- Compare forecast ROAS with your break-even ROAS before deciding.
- Use mature data. Early weeks often differ from steady state.
- Record your assumptions so the next review can check them.
Put it to work
Keep the evidence beside the decision.
Record budget, cost per click, conversion rate, order value, and margin for a base, low, and high case.
Download the ROAS forecast worksheetCommon questions
How do you forecast ROAS before spending?
Divide budget by cost per click to get clicks. Multiply by conversion rate for orders and by average order value for revenue. Divide revenue by spend.
What is a good ROAS for Google Ads?
It depends on your margin and costs. Work out your break-even ROAS first. Anything above it adds profit before fixed costs.
Why add repeat orders to a forecast?
A first-order forecast ignores customers who buy again. If your customers do return, the true return is higher than the first-order ROAS shows.
How accurate is a forecast?
It is as accurate as its inputs. Use your own data where you can and test a low and a high case.
Sources and method
This guide combines the linked sources with Ad Prophet's editorial methods and original decision aids. Numerical examples are illustrative. They do not describe client results or industry benchmarks.