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Methodology

Supplier Cost Increase Impact Planner methodology

Choose a price or volume response to a supplier cost increase.
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

Required Price Ex Tax
requiredPriceExTax = new total unit cost ÷ (1 − baseline margin)

Where

newUnitCostExTax
New unit cost (currency units/product unit, ex tax)Source: Business record
requiredPriceExTax
Required Price Ex Tax (currency units, ex tax)Source: Calculated output
Period Profit Loss Ex Tax
periodProfitLossExTax = (new unit contribution − old unit contribution) × volume

Where

volume
Current volume (whole product units/comparison period)Source: User assumption
periodProfitLossExTax
Period Profit Loss Ex Tax (currency units, ex tax)Source: Calculated output
Incremental Cash Cost Ex Tax
incrementalCashCostExTax = (new supplier cost − old supplier cost) × volume

Where

oldUnitCostExTax
Old unit cost (currency units/product unit, ex tax)Source: Business record
newUnitCostExTax
New unit cost (currency units/product unit, ex tax)Source: Business record
volume
Current volume (whole product units/comparison period)Source: User assumption
incrementalCashCostExTax
Incremental Cash Cost Ex Tax (currency units, ex tax)Source: Calculated output
Required Volume
requiredVolume = ceil(baseline period contribution ÷ planned unit contribution)

Where

volume
Current volume (whole product units/comparison period)Source: User assumption
requiredVolume
Required Volume (operational units)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 worked rows below come directly from the registered engine and visible default fixture.

Calculation and outputs

Example

The worked rows below come directly from the registered engine and visible default fixture.

Required Price Ex Tax
89.6 currency units
Period Profit Loss Ex Tax
-6,000 currency units
Incremental Cash Cost Ex Tax
6,000 currency units
Required Volume
1,000

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

Interpretation

The protected-price result shows the response required to preserve the selected commercial outcome after the supplier increase.

3. Validation and boundary checks

  • All inputs must be finite and within the visible validation boundaries.
  • Rates use decimal values below 100%; whole-unit thresholds round upward only where the engine names that rule.
  • All compared monetary inputs use one consistent ex-tax basis and planning period.

4. Assumptions and source classification

  • Every cost, price, fee and volume is supplied by the user; no market benchmark is inferred.
  • Indirect tax is excluded from retained commercial economics unless a dedicated input explicitly models it.
  • The engine retains full precision and display formatting never feeds back into calculation.

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 model does not forecast demand, competitor response, supplier negotiation outcomes or capacity.
  • It does not replace accounting, tax, legal or financial 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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