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Structured methodology As of 2026-04-24

How Ad Spend / ROAS Calculator works

What the tool assumes, what data it pulls from, and what it cannot tell you.

Education · General business information, not legal, tax, or financial advice. Editorial standards Sponsor disclosure Corrections

1. Scope

Converts ad spend, impressions, clicks, and conversions into ROAS, break-even ROAS, profit after spend, and the conversion rate required to hit a target. It does not include platform fees, incrementality adjustments, or multi-touch attribution.

2. Inputs and outputs

Inputs

  • ad_spend number (currency)
  • revenue_generated number (currency)

    Revenue from the ads. Alternatively supply conversions + average_order_value.

  • conversions number

    Optional — used with average_order_value when revenue is not given directly.

  • average_order_value number (currency)

    Optional companion to conversions.

  • product_cost number (currency)

    COGS per unit/order.

  • target_profit_margin_percent percent

Outputs

  • revenue / actualRoas

    Revenue and revenue / ad_spend.

  • cogs / grossProfit

    conversions × product_cost, and revenue − cogs.

  • profitAfterAdSpend / profitMarginPercent

    grossProfit − ad_spend, and that over revenue.

  • breakEvenRoas

    1 / (1 − cogs/revenue).

  • targetCpa / requiredConversionRate / roasHealth / guidance

    Max CPA and conversions to hit the target margin, a health band, and guidance.

Engine source: src/lib/ad-spend-roas-calculator/engine.ts

3. Formula / scoring logic

revenue        = revenue_generated  (or conversions * average_order_value)
actual_roas    = revenue / ad_spend
cogs           = conversions * product_cost
profit_after_ad_spend = revenue - cogs - ad_spend
breakeven_roas = 1 / (1 - cogs / revenue)

4. Assumptions

  • Revenue is entered directly (or via conversions × AOV); the tool does not derive it from clicks × conversion rate.
  • COGS is per order (conversions × product_cost); it is netted before profit, so ROAS and profit differ.
  • Platform fees, ad agency fees, and returns are assumed to be zero or already netted.

5. Data sources

6. Known limitations

  • ROAS is not profit. A 4:1 ROAS at 25% margin breaks even; at 60% margin, it's highly profitable. Always check against breakeven ROAS.
  • Incrementality requires a hold-out test (geo-split or audience hold-out). Without it, reported ROAS can overstate channel value meaningfully.

7. Reproducibility

Input
ad_spend = $5,000, conversions = 200, average_order_value = $75, product_cost = $20, target_profit_margin_percent = 30.

Expected output
revenue = $15,000, actualRoas = 3.0×, cogs = $4,000, grossProfit = $11,000, profitAfterAdSpend = $6,000, profitMarginPercent = 40, breakEvenRoas ≈ 1.36×.

8. Change log

  • 2026-04-24 methodology page first published.

Worked example

Run live against the same engine this site ships (/engines/ad-spend-roas-calculator.js). The inputs and outputs below are recomputed on every build and independently re-verified in CI — they are never hand-authored.

Input

tool
ad_spend_roas_calculator
ad_spend
5000
revenue_generated
20000
product_cost
20
target_profit_margin_percent
20

Output

revenue
20000
actualRoas
4
breakEvenRoas
1
profitAfterAdSpend
14980
profitMarginPercent
74.9
targetCpa
15980
requiredConversionRate
31.29
roasHealth
Excellent
guidance
ROAS of 4× is well above break-even. Scale budget confidently while monitoring marginal ROAS at higher spend levels.
cogs
20
grossProfit
19980

Frequently asked questions

What does the Ad Spend / ROAS Calculator calculate?
Converts ad spend, impressions, clicks, and conversions into ROAS, break-even ROAS, profit after spend, and the conversion rate required to hit a target. It does not include platform fees, incrementality adjustments, or multi-touch attribution.
What inputs does the Ad Spend / ROAS Calculator need?
It takes 6 inputs: ad_spend, revenue_generated, conversions, average_order_value, product_cost, target_profit_margin_percent. Outputs returned: revenue / actualRoas, cogs / grossProfit, profitAfterAdSpend / profitMarginPercent, breakEvenRoas, targetCpa / requiredConversionRate / roasHealth / guidance.
What formula does the Ad Spend / ROAS Calculator use?
The exact computation is: revenue = revenue_generated (or conversions * average_order_value); actual_roas = revenue / ad_spend; cogs = conversions * product_cost; profit_after_ad_spend = revenue - cogs - ad_spend; breakeven_roas = 1 / (1 - cogs / revenue)
Can I verify the Ad Spend / ROAS Calculator with a worked example?
Yes. With ad_spend = $5,000, conversions = 200, average_order_value = $75, product_cost = $20, target_profit_margin_percent = 30. the tool returns revenue = $15,000, actualRoas = 3.0×, cogs = $4,000, grossProfit = $11,000, profitAfterAdSpend = $6,000, profitMarginPercent = 40, breakEvenRoas ≈ 1.36×.
Where does the Ad Spend / ROAS Calculator get its benchmark data?
Reference data is sourced from: US FTC ad-attribution guidance (Endorsement Guides) (as of 2023).
What can the Ad Spend / ROAS Calculator not tell me?
Known limitations: ROAS is not profit. A 4:1 ROAS at 25% margin breaks even; at 60% margin, it's highly profitable. Always check against breakeven ROAS. Incrementality requires a hold-out test (geo-split or audience hold-out). Without it, reported ROAS can overstate channel value meaningfully.