ROAS Genius is a free, browser-only calculator that turns raw revenue and spend numbers into the two figures that actually predict whether an e-commerce business is healthy: blended MER and net contribution margin.
We built ROAS Genius because we kept watching the same mistake happen across dozens of ad accounts: a founder or media buyer would see a strong ROAS number on their best-performing platform and scale spend, only to find net profit falling anyway. The gap wasn't bad advertising — it was measuring the wrong thing. Platform-reported ROAS answers "how did this channel perform, by its own accounting." It was never designed to answer "is the business making money," and since Apple's App Tracking Transparency changes in 2021, it has become progressively worse at even answering its original, narrower question.
Our mission is narrow and specific: give any e-commerce operator, regardless of ad budget or technical sophistication, a way to compute the two or three numbers that actually govern a scale-or-cut decision, in under sixty seconds, without installing anything, connecting an ad account, or sending data anywhere.
Every calculation ROAS Genius performs is listed below in full. There is no hidden weighting, no proprietary "efficiency score," and no benchmark data pulled from other users — every number comes only from what you type in.
This treats all ad spend as one pool regardless of platform, avoiding the double-counting and inflated modeled conversions that occur when individual platform ROAS figures are compared or summed.
Shipping and fulfillment is entered as a flat dollar figure for the period rather than a percentage, since fulfillment cost is typically driven by order count and weight rather than order value.
This is the blended MER at which total ad spend would exactly equal the contribution margin remaining after COGS, fees, and shipping — the threshold below which further spend actively destroys profit.
The sensitivity slider models diminishing marginal returns: a higher sensitivity value assumes efficiency degrades faster as budget increases (or improves faster as budget decreases), which is a reasonable approximation of real auction behavior but remains a simulation, not a guarantee.
We do not accept payment from Meta, TikTok, Google, or any ad platform, and nothing in our methodology favors one channel's numbers over another's.
Every figure the simulator produces traces back to a documented formula on this page. We do not use undisclosed weighting, machine learning, or "proprietary scoring."
All calculations run client-side in JavaScript. The numbers you enter are stored only in your own browser's local storage, never on our servers.
ROAS Genius is a calculator and educational resource, not a substitute for a qualified accountant, tax advisor, or financial planner familiar with your specific business.
Primarily direct-to-consumer e-commerce founders, in-house media buyers, and agency account managers who need a fast, cross-platform sanity check before requesting or approving a budget change.
No. You type in totals manually, which takes under a minute per period and means no API access, no login, and no data sharing with any ad platform is ever required.
The formulas are stable by design — they are standard contribution-margin accounting rather than a model that needs retraining. We revisit the educational guide when attribution or platform reporting changes materially affect how the numbers should be interpreted.
No. ROAS Genius estimates operating-level marketing efficiency for fast decision-making. Tax treatment, accrual accounting, and full P&L reporting should still go through a qualified accountant.