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Methodology

ROAS to Contribution Planner methodology

This planner converts contribution before advertising into acquisition-cost and ROAS thresholds and compares entered campaign performance.
Duc Nguyen X.By Duc Nguyen X.· Founder, Margin101Last reviewed: View update historyMethodology

Educational only: Business decision support, not accounting, tax or legal advice.

Privacy: Calculations run locally; Margin101 does not receive your commercial inputs.

Update policy: Reviewed when formulas or official dependencies change.

Scope: Market-neutral small-business planning using your own assumptions.

1. Formulas and units

Break-even acquisition cost
CPAᵦ = C

Where

C
contribution before ads (currency units/order)Source: Business record
CPAᵦ, CPAₜ, CPAₐ
break-even, target and actual acquisition cost (currency units/order)Source: Calculated output
Break-even revenue ROAS
ROASᵦ = R ÷ C

Where

R
revenue per acquired order excluding indirect tax (currency units/order)Source: Business record
C
contribution before ads (currency units/order)Source: Business record
ROASᵦ, ROASₜ, ROASₐ
break-even, target and actual revenue return on ad spend (ratio)Source: Calculated output
Target acquisition cost
CPAₜ = C − T

Where

C
contribution before ads (currency units/order)Source: Business record
T
contribution to retain (currency units/order)Source: User decision
CPAᵦ, CPAₜ, CPAₐ
break-even, target and actual acquisition cost (currency units/order)Source: Calculated output
Target revenue ROAS
ROASₜ = R ÷ (C − T)

Where

R
revenue per acquired order excluding indirect tax (currency units/order)Source: Business record
C
contribution before ads (currency units/order)Source: Business record
T
contribution to retain (currency units/order)Source: User decision
ROASᵦ, ROASₜ, ROASₐ
break-even, target and actual revenue return on ad spend (ratio)Source: Calculated output
Actual acquisition cost
CPAₐ = S ÷ N

Where

S
campaign spend (currency units/period)Source: Business record
N
acquired orders (orders/period)Source: Business record
CPAᵦ, CPAₜ, CPAₐ
break-even, target and actual acquisition cost (currency units/order)Source: Calculated output
Actual revenue ROAS
ROASₐ = (R × N) ÷ S

Where

R
revenue per acquired order excluding indirect tax (currency units/order)Source: Business record
S
campaign spend (currency units/period)Source: Business record
N
acquired orders (orders/period)Source: Business record
ROASᵦ, ROASₜ, ROASₐ
break-even, target and actual revenue return on ad spend (ratio)Source: Calculated output
Campaign contribution
P = (C × N) − S

Where

C
contribution before ads (currency units/order)Source: Business record
S
campaign spend (currency units/period)Source: Business record
N
acquired orders (orders/period)Source: Business record
P, Pₜ, G
campaign contribution, target total and target gap (currency units/period)Source: Calculated output
Target contribution total
Pₜ = T × N

Where

T
contribution to retain (currency units/order)Source: User decision
N
acquired orders (orders/period)Source: Business record
P, Pₜ, G
campaign contribution, target total and target gap (currency units/period)Source: Calculated output
Acquisition-cost headroom
H = CPAₜ − CPAₐ

Where

CPAᵦ, CPAₜ, CPAₐ
break-even, target and actual acquisition cost (currency units/order)Source: Calculated output
H
acquisition-cost headroom (currency units/order)Source: Calculated output
Target gap
G = P − Pₜ

Where

P, Pₜ, G
campaign contribution, target total and target gap (currency units/period)Source: Calculated output

Money inputs and outputs use the currency selected in the scenario without changing the canonical methodology. Rates, margins, utilisation and buffers are entered as percentages and converted to decimal values for calculation.

2. Worked example

Input assumptions

The default fixture uses only user-entered records; every row below is formatted from the engine result.

Calculation and outputs

Example

The default fixture uses only user-entered records; every row below is formatted from the engine result.

Break-even CPA
40.00 currency units
Target CPA
30.00 currency units
Break-even ROAS
2.50x
Target ROAS
3.33x
Actual CPA
24.00 currency units
Actual ROAS
4.17x
Campaign contribution
1,600.00 currency units
Target contribution total
1,000.00 currency units
Acquisition-cost headroom
6.00 currency units
Gap to target
600.00 currency units
Decision state
Above target

The exact engine-derived outputs are shown in the labelled rows below.

Interpretation

Use contribution-based ROAS and target CPA as spending boundaries, not as guarantees of campaign demand or attribution.

3. Validation and boundary checks

  • Target contribution must be below contribution before ads.
  • Zero spend or zero orders produces only the ratios with valid denominators; zero spend and zero orders together is insufficient data, never break-even.
  • Target gap equals acquisition-cost headroom multiplied by acquired orders when actual CPA exists.

4. Assumptions and source classification

  • All values are user supplied, exclude indirect tax and use one consistent attributed-order basis.
  • No platform, industry, attribution or conversion benchmark is used.

This planner has no current policy-data dependency. Its commercial assumptions are user supplied. Registered family-level regression suites exercise the shared business-logic engine and worked-result reconciliation.

5. Limitations

  • Attributed orders may not equal incremental customers; revenue ROAS does not measure profit by itself.
  • The model excludes refunds not already included in contribution, uncertain cash timing and tax advice.

This is educational decision support, not tax, accounting, legal or financial advice. Check the treatment of your actual transactions under the rules that apply to your business and seek qualified advice where appropriate.

6. Update and evidence policy

Registered family-level suites test formula invariants and example reconciliation; the release ledger records that coverage without claiming a separate oracle for every line of public copy. There is no official threshold or benchmark to refresh for this planner. Commercial inputs remain user-supplied because they vary by business and contract.

Change history

  1. : Initial public release of the planner and methodology after pre-launch calculation, content, source and interaction review.

Related reading

Guides to interpret the decision and its assumptions.

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