Free eCommerce calculator
Find the ROAS your order economics can actually support.
Calculate contribution before advertising, break-even CPA, break-even ROAS, target CPA and target ROAS from the economics of a representative order.
Start with the money left after variable costs, then decide how much of that contribution you are willing to spend acquiring the order.
Break-even ROAS calculator
What can one order afford to spend on advertising?
The pre-filled values are a hypothetical example. Replace them with consistent order-level numbers from your business. Use the same currency for every field.
Read the inputs consistently
The formula is simple. The definitions matter.
Most errors come from mixing accounting bases, double-counting losses or treating order economics as customer economics.
Use consistent revenue
Use revenue net of sales tax and on a consistent discount and refund basis. If revenue already reflects expected refunds, do not subtract that same loss again.
Use shipping subsidy
Shipping subsidy is the shipping cost you absorb after any shipping revenue, rather than automatically the full delivery cost.
Contribution is not net profit
Fixed overhead and your desired profit buffer still need to be covered by the post-ad contribution.
Order CPA is not always CAC
An order CPA is not customer CAC unless every measured order represents one newly acquired customer.
Keep one currency
Use the same currency for all fields. This calculator displays euros.
Avoid double counting
Each cost or loss should be represented once on the basis you have chosen for the calculation.
The formulas
Work from contribution to the target.
The calculator follows the formulas from the original page.
The default values
Important limits
Some economics produce no positive advertising allowance.
A calculator should surface that conclusion rather than force a ROAS target.
Contribution ≤ €0
If contribution is zero or negative, no positive advertising spend breaks even under these assumptions.
Desired contribution is too high
If the desired post-ad contribution equals or exceeds the available contribution, there is no positive target CPA.
ROAS is an output here
The useful sequence is to define consistent order economics, then derive the break-even and target advertising allowance.
Need the account reviewed too?
The right ROAS target is only one part of the diagnosis.
The €650 eCommerce Diagnostic reviews the wider system, including economics, purchase measurement, Merchant Center, product feeds, campaign structure and the store experience.
Continue the diagnosis
Put the number back into the wider acquisition system.
Use the supporting guides to investigate profitability, measurement and the rest of the account.
Google Ads profitability
Move from reported revenue toward contribution and a defensible acquisition allowance.
Read the profitability framework41-point account checklist
Review economics, measurement, Merchant Center, feeds, campaigns, product pages and reporting.
Review the acquisition systemPurchase tracking
Review transaction IDs, purchase values, currency and duplicate purchase signals.
Read the purchase tracking guideCalculator FAQ
Common questions about the inputs and outputs.
What revenue number should I enter?
Use revenue net of sales tax and on a consistent discount and refund basis. If the revenue figure already reflects expected refunds, do not subtract the same expected loss again in the returns field.
Is contribution before advertising the same as net profit?
No. Contribution before advertising is the amount left after the variable costs listed in the calculator. Fixed overhead and your desired profit buffer still need to be covered by the post-ad contribution.
Is the target CPA the same as customer acquisition cost?
Not necessarily. The calculator derives an order-level CPA. An order CPA is customer CAC only when every measured order represents one newly acquired customer.
What happens if contribution is zero or negative?
No positive advertising spend breaks even under those assumptions. The calculator therefore does not produce a positive break-even CPA or ROAS target.
Are the values I enter sent anywhere?
The calculator runs client-side in your browser. The calculator code does not send the values you enter to analytics or a third-party calculation service.
From target to account decision
Know what an order can afford. Then diagnose what is stopping the account.
If the economics are clear but the next account action is not, use the €650 eCommerce Diagnostic to turn the evidence into a prioritised roadmap.