How to calculate ecommerce profit per paid order after costs
This per-order model reduces average order value for the expected refund rate, removes included sales VAT, and subtracts COGS, outbound shipping, fulfillment, and payment processing. The remainder is the acquisition allowance before the order reaches zero contribution.
CPA at the entered ROAS equals gross AOV divided by ROAS. Subtracting that CPA from the acquisition allowance estimates paid-order profit. The result is most useful when inputs match the same product mix and reporting period.
Profit = net sales after refunds and VAT − variable costs − CPAEcommerce ROAS worked example with AOV and COGS
Assume $100 gross AOV, a 10% expected refund rate, $30 COGS, $7 shipping, $3 fulfillment, and $3 payment cost, with no sales tax in this simplified example. Expected sales after refunds are $90 and non-ad costs total $43, leaving a $47 acquisition allowance.
At 3.00x ROAS, CPA is $100 divided by 3, or $33.33. Estimated first-order profit is therefore $47 minus $33.33, or $13.67 per attributed order. This result changes when the ad platform reports net revenue, when refunded goods retain value, or when costs vary by product mix.
How to find ecommerce break-even ROAS and maximum CPA
Maximum CPA is the amount left after non-ad variable costs. Break-even ROAS divides the platform revenue basis by that CPA. Actual ROAS above the floor implies positive first-order contribution under the entered assumptions; actual ROAS below it implies negative contribution.
Returns, discounts, free shipping, and mixed tax treatment can move the threshold quickly. Recalculate for major promotions and product categories instead of applying one store-wide target to every campaign.
Storewide ROAS vs product-level ROAS for ecommerce
Storewide ROAS can summarize the paid portfolio, but it blends products with different AOV, COGS, refund rates, repeat behavior, and promotion depth. A store may clear its aggregate target while a high-volume product loses contribution on each paid order.
Use product or category inputs when campaigns and landing pages isolate that merchandise. Use a weighted store model when product-level attribution is unavailable, and document the period and product mix so the threshold is not reused after a major promotion or assortment change.
Ecommerce ROAS and paid-order profit calculator FAQ
How are refunds modeled?
The calculator reduces expected gross revenue by the entered refund rate. It does not model return shipping, damaged inventory, restocking, chargebacks, or partial refunds; include those in costs when material.
Why is AOV used in the ROAS numerator?
Many ad platforms report gross customer-paid conversion value. If your platform uses net sales instead, enter the matching value so the ROAS numerator and platform report stay comparable.
Does the result include fixed overhead?
No. It is a per-order contribution model. Add an allocated overhead amount or use a monthly P&L model when fixed costs must be recovered by paid orders.