ROAS and break-even calculator · Parable
Good ROAS. But is your ad budget right?
Calculate your return on ad spend (ROAS) and the return needed to break even. Then see why being above that threshold does not necessarily mean you should spend more.
Your numbers
Example values are filled in. Enter dollar amounts in one currency and use the same period for sales and costs. Keep tax treatment consistent.
Revenue your ad platform credits to these ads, after discounts and returns. Total store revenue would give a blended return instead.
What you paid for the products in those attributed sales.
For those sales, include payment fees, shipping you cover and other variable costs. Exclude ads and fixed costs.
What you spent on those ads in the same period.
Calculated in your browser. These numbers are not sent or saved.
See my result ↓Your average return on ad spend
4.00×
Your ads are credited with $4.00 in sales for every $1 spent. That is an average across the whole budget.
- Break-even return before fixed costs
- 2.50×
- Contribution margin before ads
- 40%
- Sales needed for $10,000.00 of ads
- $25,000.00
All dollar amounts use the same currency. Minimums are rounded up. At the exact threshold, the sales cover variable costs and ads. Nothing remains for rent, salaries or profit.
A healthy average can hide extra spending that loses profit. The curve below shows how.
The number your average cannot tell you
PSA: Above break-even does not mean you are spending the right amount.
The early dollars can earn enough to keep the average looking healthy, even when the last dollars cost more than they bring back.
Average return and next-dollar return
Invented example at a 40% contribution margin. This curve is separate from your inputs.
The solid line averages the returns from all the dollars spent so far. The dotted line shows the next dollar.
Total revenue ÷ total ad spend. The kind of average a platform reports.
Below 2.50×. Another dollar no longer covers its cost.
The shaded section is spending whose next-dollar return is below break-even. The average remains above it.
The last $2,000 in this example adds about $4,001 of sales. After variable costs and the ads, that leaves $400 less profit.
From a return figure to a spending decision
How do you really determine your ads’ profitability?
Start with your history: what you spent on ads and the revenue your store made over the same periods. Instead of reducing that history to one average, use it to estimate how revenue changes as spending rises.
Then account for product costs, other selling costs, the ads themselves and fixed costs. The gap between revenue and total costs is what you keep. The budget with the widest gap is the estimated profit peak.
Revenue, total costs and the profit between them
A separate, invented monthly example from the Parable demo. Each circle represents a month of example ad spend and revenue. It is not calculated from your inputs above.
- Current example budget
- $140,000 per month
- $80,184 estimated net profit
- Budget at the estimated peak
- $110,000 per month
- $86,752 estimated net profit
Here, spending less could leave more profit. The current budget is past the estimated peak. Sales are higher, but the gap between revenue and total costs is smaller. Below the peak, the opposite can be true: spending more can leave more profit.
The blue range shows uncertainty around the estimated peak. Budgets are rounded. Net profit includes this example’s product costs, ads and fixed costs. This is an illustration, not a forecast for your store.
That is the decision Parable helps you make.
Parable uses your store’s history to estimate this relationship and show the uncertainty. History alone does not prove which sales the ads caused. Seasonality, promotions and other changes can affect the pattern, so the curve is a starting point for a small test.
The useful question becomes: would spending more, less or holding steady leave me with more profit? Test a manageable change, then compare what actually happened.
Explore an example store in Parable →01 · The calculation
Start with what a sale leaves.
Your reported ROAS is revenue attributed to ads divided by ad spend. For example, $40,000 divided by $10,000 is 4×. It is a ratio across the whole budget, not a measurement of what the next dollar will return.
Subtract product costs and variable selling costs from sales revenue. The amount left is your contribution before advertising. Divide it by revenue to find your contribution-margin percentage.
Break-even ROAS = 1 ÷ contribution-margin fraction
For example, $10,000 in sales minus $4,500 in product costs and $1,500 in other selling costs leaves $4,000. That is a 40% margin. The calculation is 1 ÷ 0.40 = 2.5. Spending $1,000 on ads therefore needs $2,500 in additional sales to cover those ads after variable costs.
This assumes the same margin applies to the extra sales. A change in product mix, discounts, delivery costs or fees can change the threshold.
02 · Include the right costs
Product margin can overstate what is left for ads.
A product that sells for $100 and costs $45 has a 55% product margin. If payment fees and shipping you cover take another $15, only $40 remains before ads. Using 55% in the calculation would make the required return look lower than it is.
Use sales and costs from the same period. Keep taxes consistent and account for discounts and returns. Include fulfilment or other costs where they rise with sales. Do not count the same shipping cost twice.
Leave fixed costs such as rent out of this contribution calculation. They still have to be paid. Reaching the calculator’s threshold is not the same as the whole business breaking even.
Common questions
What if I have no sales yet?
Use an estimated selling price and the variable costs of one order to explore a scenario. Treat that margin as an assumption to check against real orders. The calculator cannot divide by zero sales.
Does this include repeat purchases?
There is no assumed lifetime-value uplift. If you use repeat-purchase revenue, include its costs and use the same time window throughout. Cash may leave your business well before those later sales arrive.
Can this tell me how much to spend?
It calculates your reported average and the return needed under your margin assumption. It does not predict the sales a budget will cause. Platform attribution can include buyers who would have purchased anyway, and different platforms can claim the same sale.
Read the guide to spending more, less or holding →