Model Google Shopping or Performance Max profitability from CPC, conversion rate, CPA, product margin and ad spend — then see break-even CPA, ROAS, CPC and monthly profit.
Editable planning assumptions. Verify current fees against your account, product and platform terms.
Choose the reporting style you want to model.
Use either real account data or a planning scenario.
Use only if you have a documented CSS commercial benefit. Google requires CSS participation for Shopping ads in listed CSS program countries, but partner pricing models vary.
The calculator above joins two sets of numbers that are often reviewed separately: paid-media performance and product economics. Enter campaign spend, CPC or conversion assumptions, selling price, product cost, fulfillment, payment fees, returns and other order costs. The results card converts those inputs into projected orders, CPA, ROAS, profit per order, net margin, break-even CPA and break-even ROAS. This prevents a high ROAS from being treated as profitable when product and fulfillment costs leave little contribution margin.
Google Shopping ads are not modeled as a marketplace referral fee. Google Ads charges according to the campaign's billing model; standard Shopping campaigns commonly use cost-per-click. Merchant Center free listings are a separate traffic source. Payment, ecommerce platform and fulfillment charges still belong in the order economics.
ROAS and profit answer different questions. ROAS measures revenue efficiency of ad spend. Profit subtracts the costs required to create and fulfill the order. A campaign can exceed 3× ROAS and still be weak if the product has a high cost ratio or expensive fulfillment.
Assume an $80 order with $32 product cost, $8 fulfillment, a 2.9% + $0.30 payment fee, a 2% refund reserve and $2 of other variable cost. Non-ad cost is $46.22, leaving $33.78 as the maximum acquisition cost before modeled profit reaches zero. Break-even ROAS is therefore about 2.37×. If average CPC is $0.60 and conversion rate is 3%, expected CPA is $20. At that CPA, ROAS is 4.0× and modeled order profit is $13.78, or about a 17.2% margin.
| Cost or metric | Example | Role in the model |
|---|---|---|
| Google Ads click cost | $0.60 CPC | Paid-media cost; not a marketplace referral fee |
| Conversion rate | 3% | Converts CPC into expected CPA |
| Payment processing | 2.9% + $0.30 example | Store-side transaction cost |
| Product + fulfillment | $40 | Core non-ad unit cost |
| Refund reserve + other | $3.60 | Planning allowance for additional variable cost |
This example assumes attributed revenue equals the order value and does not attempt to solve attribution differences between Google Ads, analytics and your ecommerce platform. Use one consistent revenue definition when comparing periods.
Shopping ads are generally billed through Google Ads based on campaign performance such as clicks, not as a marketplace referral percentage on each order. Your store and payment-provider fees are separate.
Break-even ROAS is the minimum modeled revenue-to-ad-spend ratio that covers the non-ad costs entered in the calculator.
Maximum CPC equals the break-even acquisition cost multiplied by conversion rate. A higher conversion rate allows a higher CPC at the same unit economics.
Yes. Use the campaign spend, revenue, CPC or conversion assumptions that match your reporting. The calculator is an economics model, not a bidding recommendation.
Google Ads billing and Shopping references checked September 25, 2026 against Google Ads Shopping documentation. See our break-even ROAS guide.
An $80 order with $50 non-ad costs breaks even at 2.67× ROAS. A 15% margin target requires keeping $12, leaving $18 for advertising and raising the needed ROAS to 4.44×.
At a hypothetical 2% conversion rate, that $18 CPA corresponds to $0.36 CPC. This is a planning relationship, not an auction prediction. Use a consistent revenue definition.
Original hypothetical worked example. Read the guide for all assumptions, formulas and exclusions.