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Methodology

SaaS Gross Margin Planner methodology

Reconcile a user-defined recurring service cost stack against revenue without imposing an accounting classification or target benchmark.
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

Cost of service
costOfService = hosting + support + third-party service + payment fees + implementation

Where

hostingCost
Hosting cost (currency units on one consistent basis)Source: Business record
supportCost
Support cost (currency units on one consistent basis)Source: Business record
thirdPartyServiceCost
Third-party service cost (currency units on one consistent basis)Source: Business record
paymentFees
Payment fees (currency units on one consistent basis)Source: Business record
implementationCost
Implementation service cost (currency units on one consistent basis)Source: Business record
costOfService
Cost of service (money)Source: Calculated output
Gross contribution
grossContribution = recurring revenue − cost of service

Where

recurringRevenue
Recurring revenue (currency units on one consistent basis)Source: Business record
costOfService
Cost of service (money)Source: Calculated output
grossContribution
Gross contribution (money)Source: Calculated output
Gross margin
grossMargin = gross contribution ÷ recurring revenue

Where

recurringRevenue
Recurring revenue (currency units on one consistent basis)Source: Business record
grossContribution
Gross contribution (money)Source: Calculated output
grossMargin
Gross margin (percent)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

Worked values below come from the same registered engine and visible default assumptions.

Calculation and outputs

Example

Worked values below come from the same registered engine and visible default assumptions.

Cost of service
4,000.00 currency units
Gross contribution
6,000.00 currency units
Gross margin
60%

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

Interpretation

Use the reconciled cost stack to identify which user-classified service costs consume recurring contribution; it is not an accounting-standard classification.

3. Validation and boundary checks

  • Revenue and all five user-classified cost layers must be finite and non-negative.
  • Cost of service must equal the exact five-cost sum.
  • Negative calculated contribution and margin remain valid when cost exceeds revenue.
  • Zero revenue returns a zero margin rather than Infinity or NaN.

4. Assumptions and source classification

  • Every cost layer is included because the user classifies it as cost of service for this decision.
  • No accounting policy, target benchmark or market default is embedded.

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

  • The result does not determine accounting-standard gross margin or recommend a target margin.
  • It does not replace financial, accounting, tax or legal 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 SaaS Gross Margin planner and methodology.

Related reading

Guides to interpret the decision and its assumptions.

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