E-Commerce Contribution Margin, POAS & Break-Even ROAS Calculator
Interactive financial unit-economics modeller calculating net contribution margin, Profit on Ad Spend (POAS), break-even ROAS and scaling scenarios.
E-Commerce Contribution Margin, POAS & Break-Even ROAS Modeller
Live Client-Side CalculationPlatform-reported ROAS hides the true cost of inventory, merchant fees, shipping, fulfilment and returns. Use this model to calculate your true break-even ROAS and net profit per order.
Order Economics & Unit Costs
Estimated cost: $42.00
Key Profit & Efficiency Metrics
Break-Even ROAS
2.21x
Target CPA cap: $54.38
Net Profit / Order
+$19.38
16.15% net margin
Current ROAS (Reported)
3.43x
Target CPA: $35
Profit on Ad Spend (POAS)
1.55x
Gross margin / CPA
Per-Order Cost & Margin Breakdown
- Gross Revenue (AOV):$120.00
- Less Returns & Refunds (6%):-$7.20
- Cost of Goods Sold (COGS):-$42.00
- Payment Gateway Fee:-$3.42
- Shipping & Fulfilment:-$13.00
- Gross Contribution Margin:$54.38 (45.32%)
- Advertising Spend (Target CPA):-$35.00
- Net Contribution Margin:$19.38 (16.15%)
Monthly Scaling Projections ($15,000 Spend)
Projected Orders428
Projected Gross Revenue$51,360
Projected Net Profit$8,294.64
Replacing Surface ROAS with Net Contribution Margin
Platform-reported ROAS from Google Ads and Meta Ads flatters digital performance by ignoring cost of goods sold (COGS), payment gateway transaction fees, picking and packing, shipping overhead, and return rates. This calculator reveals true net profit per acquired customer.
How to cite and attribute this tool
MIT LicenceThis resource is free, open and un-gated under the MIT Open Source Licence. You are encouraged to use, integrate and cite it with attribution:
Geraghty, G. (2026). E-Commerce Contribution Margin, POAS & Break-Even ROAS Calculator. Gordon Geraghty Resources Hub. https://gordongeraghty.com/resources/performance-media/ecommerce-contribution-margin-poas-calculator
BibTeX Format
@misc{geraghty_ecommerce_contribution_margin_poas_calculator,
author = {Geraghty, Gordon},
title = {E-Commerce Contribution Margin, POAS & Break-Even ROAS Calculator},
year = {2026},
url = {https://gordongeraghty.com/resources/performance-media/ecommerce-contribution-margin-poas-calculator},
note = {Head of Performance, Empire Amplify}
}Changelog & Version History
v1.0.0Initial release with dynamic ROAS/POAS sensitivity modelling and return rate factor.