What break-even ROAS measures
ROAS is attributed revenue divided by advertising spend. A 2.0x ROAS means $2 in attributed sales for each $1 spent on ads; it says nothing by itself about the product cost, fulfillment or payment fees behind those sales. Break-even ROAS adds those order costs to find the point where contribution after ads is zero.
This calculator treats one retail order as the unit of analysis. It works best when the selling price and costs represent the same order or a consistent average order value, rather than a mixture of products with very different margins.
The formula behind the three outputs
First calculate the gateway fee: selling price × gateway fee percentage. Then pre-ad profit = selling price − total COGS − shipping and handling − gateway fee. Pre-ad profit margin % = pre-ad profit ÷ selling price × 100. Max allowable CPA equals that pre-ad profit.
When pre-ad profit is positive, break-even ROAS = selling price ÷ pre-ad profit. This is the same as 1 ÷ pre-ad margin expressed as a decimal, not 1 divided by the percentage number. A 40% margin is 0.40 in the equation, so its break-even ROAS is 2.50x.
A worked example: $60 product and 3% processing fee
For a $60 order with $18 COGS, $6 shipping and a 3% gateway fee, processing costs $1.80. Pre-ad profit is $34.20, pre-ad margin is 57.0%, max CPA is $34.20, and break-even ROAS is $60 ÷ $34.20, or about 1.75x.
At a planned 2.0x ROAS, implied ad spend for that $60 order is $30 and modeled contribution after ads is $4.20. At 1.5x, implied ad spend is $40 and the order loses $5.80. The slider above helps you see the same boundary without changing the core order inputs.
Read the red and green safety zone correctly
The red portion is below the calculated break-even ROAS; the green portion is above it. Move planned ROAS to compare a possible campaign outcome with the threshold. If pre-ad contribution is zero or negative, there is no finite ROAS that makes this single order profitable under the current inputs.
Green does not mean your target profit has been met. It means the simplified per-order model has crossed zero. Refunds, discounts, overhead and a desired profit margin all require more headroom above break-even.
ROAS and CPA describe the same ad-spend ceiling
Max CPA is the most this order can spend on acquisition before modeled contribution reaches zero. Break-even ROAS expresses that same ceiling as revenue divided by spend. If you increase selling price without increasing costs, the CPA ceiling usually grows and break-even ROAS falls. If COGS or shipping rises, the opposite happens.
Use actual blended acquisition data carefully. A platform-reported ROAS may attribute revenue differently from your store's order records, and repeat orders can distort a new-customer CPA comparison. Match the time period and measurement basis before using a threshold to change budget.
Choose inputs that match your checkout
Use a selling price before sales tax and the COGS for the same order. Shipping and handling should be the amount your business pays, including packaging or pick-and-pack costs when material. The gateway fee input models a percentage of selling price; it does not include a fixed charge per transaction.
If a fixed processing charge matters, add it to the order-level costs for a rough scenario or use the Shopify and Stripe fee calculator, where percentage and fixed charges can be entered separately. Avoid counting the same processing fee twice.
When to calculate again
Recalculate after a price change, promotion, supplier increase, new shipping zone or payment-method change. A break-even figure copied from a different product or an old campaign can give a false sense of safety because its cost stack no longer matches the order you are buying.
Treat the result as a planning estimate. To evaluate business profit, reconcile it with actual payouts, returns, taxes and fixed operating costs.