Platform ROAS is not profit. A campaign can report 3× ROAS and still lose money once COGS, platform and payment fees, shipping subsidies, returns, and fixed overhead consume the margin. This calculator finds your true ROAS floor — marginal and business-level — plus the target ROAS for a desired net margin, your max CAC (first-order and LTV-adjusted), break-even MER, and the maximum ad budget your P&L can carry. Built for ecommerce, DTC, marketplace sellers, agencies, and small-business advertisers.
Ad platforms may over- or under-attribute revenue.
Break-even ROAS = 1 ÷ effective contribution margin. A product with a 50% gross margin, 3% fees, a 7% shipping subsidy, and a 5% return rate keeps (50 − 3 − 7) × (1 − 0.05) = 38% of attributed revenue — so its break-even ROAS is 1 ÷ 0.38 ≈ 2.63×. A 3× campaign on it earns $350 per $2,500 of spend; the same 3× on a 15.6%-margin product loses money. Fixed overhead raises the business-level floor further.
Calculator
Simple ROAS Floor
%
Revenue left after product cost, before fees and shipping.
%
%
Share of revenue you absorb as shipping cost.
%
$
$
What your ad platform attributes to this spend.
Values are saved locally as you type. Sharing builds a link with your numbers embedded in it — no server involved.
Attributed revenue ÷ ad spend — 14% above the floor.
Profit / loss after ads
$350
Attributed revenue × effective margin − ad spend.
Effective contribution margin
38%
40% before returns.
Max CAC as % of revenue
38%
You can spend at most this share of attributed revenue on acquisition.
Safety buffer
0.37×
Actual ROAS − break-even ROAS.
Estimate only — not accounting, tax, legal, investment, or financial advice. Platform ROAS may over- or under-attribute revenue.
10 sheets generated from your inputs with live formulas: simple floor, full P&L ROAS, AOV/CAC model, a 20-row SKU comparison, scenarios, sensitivity tables, and a charts dashboard.
What's driving the result
Plain-English reading of the current inputs — planning signals, not verdicts.
Biggest drag on your ROAS floor
Shipping subsidy takes 7.0 points of revenue — threshold offers or partial charges win some of it back.
ROAS zones
Below 2.63× ads lose money. The marker shows your actual ROAS.
0×break-even 2.63×4.2×
Red = loss-making zone · green = profitable. Your actual ROAS is 3×.
Break-even ROAS sensitivity
Gross margin (rows) × return rate (columns), at your current 3% fees and 7% shipping subsidy. Greener = a lower, easier floor.
Break-even ROAS by gross margin and return rate
Margin ↓ / Returns →
0%
5%
10%
15%
20%
20%
10
10.53
11.11
11.76
12.5
30%
5
5.26
5.56
5.88
6.25
40%
3.33
3.51
3.7
3.92
4.17
50%
2.5
2.63
2.78
2.94
3.13
60%
2
2.11
2.22
2.35
2.5
70%
1.67
1.75
1.85
1.96
2.08
— means the effective margin is zero or negative at that combination, so no ROAS can break even. The workbook adds fee-vs-shipping, AOV-vs-CAC, and target-margin grids.
Two floors matter here, and mixing them up is the most common reading error. The marginal floor (Simple ROAS Floor mode) answers whether one more ad-driven sale pays for itself — it needs only your effective contribution margin. The business-level floor(Full P&L mode) is stricter: fixed overhead claims its share of margin before ads can, so this floor is always higher than the marginal one. A campaign can clear the marginal floor and still bleed the P&L — the diagnosis card flags this explicitly when it happens. Treat break-even ROAS as a floor, not a goal: the target ROAS reserves your desired net margin on top of it, and that gap is your real operating corridor. Watch the break-even MER figure too if you spend across several channels — it is attribution-free and can't be gamed by overlapping attribution windows the way per-channel ROAS can.
The share of attributed revenue that can pay for ads.
Break-even ROAS (marginal)
BE ROAS = 1 ÷ ECM
Below it, every attributed sale loses money.
Business-level break-even ROAS
BE ROAS = Paid revenue share ÷ Available ad margin
Available ad margin = return-adjusted margin − overhead ÷ revenue.
Max break-even CAC
Max CAC = AOV × ECM − Fulfilment per order
Target CAC subtracts the desired first-order profit.
Worked example
A $100 AOV product with a 50% gross margin, 3% fees, a 7% shipping subsidy, and 5% returns keeps an effective contribution margin of (50 − 3 − 7) × 0.95 = 38% of attributed revenue.
Break-even ROAS = 1 ÷ 0.38 ≈ 2.63× — every attributed sale below that multiple loses money. Max CAC is 38% of revenue, or $38 on a $100 order.
At $2,500 of ad spend and $7,500 of attributed revenue (a 3.0× ROAS), profit after ads = 7,500 × 0.38 − 2,500 = $350 — about 14% above the floor: profitable, but tighter than the headline 3× multiple suggests.
Assumptions
Percentages (margin, fees, shipping, returns, discounts) are shares of revenue and are assumed to hold across the volume range analysed.
Returns scale the contribution margin multiplicatively — a returned order is treated as losing its full contribution.
The full P&L model treats fixed overhead as constant for the month and spreads it against total revenue; only the paid-attributed share of revenue answers to ROAS.
The scenario ROAS tweak moves attributed revenue at constant spend; real-world scaling usually changes efficiency too.
The four modes are independent models that share identities, not one merged dataset — each uses its own inputs, exactly as exported to the workbook.
Limitations
This is an educational planning estimate, not bookkeeping — it does not replace your P&L, accounting records, or professional advice.
Platform-reported ROAS may over- or under-attribute revenue (attribution windows, view-through conversions, channel overlap) and usually excludes returns, refunds, fees, taxes, shipping, and chargebacks.
Fixed overhead, fee schedules, and return rates drift over time — refresh the inputs from real statements (Shopify, Amazon, Meta, Google Ads, Stripe, your processor).
LTV assumptions are uncertain by nature; treat LTV-justified CAC as a hypothesis to verify with cohort data, and watch the cash-payback window.
No universal “good ROAS” exists — every verdict here is relative to YOUR margin structure, never an industry benchmark.
How do I get my real fee %, shipping subsidy, and return rate from a Shopify, Amazon, or Stripe payout statement?
Read them from real statements, not estimates. Fee % is total processing and marketplace fees ÷ revenue (Stripe, Shopify Payments, Amazon referral/FBA); shipping subsidy is the shipping cost you absorb ÷ revenue; return rate is refunded orders ÷ orders for the same period.
Why is my business-level break-even ROAS higher than the target my agency set?
Agencies usually quote a marginal or platform ROAS that ignores fixed overhead. Full P&L mode subtracts overhead from your return-adjusted margin first, so the business-level floor is higher — 1.98× in the worked example — than the lower marginal floor a platform reports. The business-level figure is the one your P&L actually feels.
Should I feed break-even ROAS or target ROAS into Google or Meta tROAS bidding?
Feed the target ROAS, not the floor. The floor only keeps you at zero; the target reserves your desired net margin first (the worked example’s corridor runs 1.98× to 2.95×). Bidding to the floor and then wondering where the profit went is a classic ecommerce mistake.
How do you calculate break-even ROAS?
Take your gross margin, subtract platform and payment fees and any shipping subsidy, then multiply by (1 − return rate) to get your effective contribution margin. Divide 1 by it. Example: (50% − 3% − 7%) × (1 − 5%) = 38%, so break-even ROAS = 1 ÷ 0.38 ≈ 2.63×.
How do I handle multiple channels that each claim the same sale?
That double-counting comes from overlapping attribution windows, inflating per-channel ROAS. Cross-check against blended MER (ad spend ÷ total revenue), which needs no attribution and can’t be gamed by window settings. Use SKU / Channel mode for per-channel floors and MER to cap total spend.
Related calculators
This page answers “what ROAS do my ads need?” — these tools take the neighbouring questions:
Ecommerce Profit CalculatorSee net profit per order after product costs, fees, shipping, ads, and returns, with break-even price and ROAS.
Profit Margin CalculatorWork out gross, contribution, operating, and net margin, with target pricing, break-even, scenarios, and SKU comparison.
Markup CalculatorPrice from cost across nine modes — markup, target margin, reverse cost ceilings, and ecommerce landed cost after fees.
Break-Even CalculatorFind units and revenue break-even, contribution margin, target profit, and margin of safety, with sensitivity tables and a chart.
LTV:CAC CalculatorCalculate CAC, discounted LTV, the LTV:CAC ratio, and CAC payback, with channel-by-channel decisions and scenarios.
This break-even ROAS calculator and its XLSX workbook are for educational estimation only. They model ad profitability from the margins, fees, return rates, overhead, and attribution figures you enter; ad platforms may over- or under-attribute revenue, and platform-reported ROAS usually excludes returns, refunds, fees, taxes, shipping, chargebacks, and fixed overhead. LTV assumptions are uncertain. This is not accounting, tax, legal, investment, or financial advice — verify costs against your accounting records and platform statements (Shopify, Amazon, Meta, Google Ads, Stripe, your payment processor) before making spending decisions.