Inventory Waste Impact Planner methodology

totalWasteUnits = spoiled + damaged + expired units

wasteRate = total waste units / available units

grossWasteCostExTax = total waste units × unit cost

netWasteCostExTax = gross waste cost − recoverable value

replacementSalesRequiredExTax = net waste cost / replacement-sales contribution rate

preventableNetCostExTax = net waste cost × prevention rate

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.

• All inputs must be finite and remain inside the visible validation boundaries.
• Whole-unit and whole-day fields reject fractional values.
• Percentages remain inside the closed range from 0% to 100%.
• Invalid denominators return an explicit unavailable result or fail closed; NaN and Infinity are never displayed.
• Spoiled, damaged and expired units combined cannot exceed available units.
• Recoverable value cannot exceed gross waste cost.

Available units minimum

availableUnits ≥ 1 whole units/measured cohort — A lower value is rejected before calculation.

Available units maximum

availableUnits ≤ 100,000,000 whole units/measured cohort — A higher value is rejected before calculation.

Spoiled units minimum

spoiledUnits ≥ 0 whole units/measured cohort — A lower value is rejected before calculation.

Spoiled units maximum

spoiledUnits ≤ 100,000,000 whole units/measured cohort — A higher value is rejected before calculation.

Damaged units minimum

damagedUnits ≥ 0 whole units/measured cohort — A lower value is rejected before calculation.

Damaged units maximum

damagedUnits ≤ 100,000,000 whole units/measured cohort — A higher value is rejected before calculation.

Expired units minimum

expiredUnits ≥ 0 whole units/measured cohort — A lower value is rejected before calculation.

Expired units maximum

expiredUnits ≤ 100,000,000 whole units/measured cohort — A higher value is rejected before calculation.

Unit cost minimum

unitCostExTax ≥ 0 currency units/unit, ex tax — A lower value is rejected before calculation.

Unit cost maximum

unitCostExTax ≤ 10,000,000 currency units/unit, ex tax — A higher value is rejected before calculation.

Recoverable value minimum

recoverableValueExTax ≥ 0 currency units/measured waste cohort, ex tax — A lower value is rejected before calculation.

Recoverable value maximum

recoverableValueExTax ≤ 10,000,000 currency units/measured waste cohort, ex tax — A higher value is rejected before calculation.

Replacement-sales contribution rate minimum

replacementSalesContributionRate ≥ 0 decimal fraction of replacement sales retained as contribution — A lower value is rejected before calculation.

Replacement-sales contribution rate maximum

replacementSalesContributionRate ≤ 1 decimal fraction of replacement sales retained as contribution — A higher value is rejected before calculation.

Prevention scenario rate minimum

preventionScenarioRate ≥ 0 decimal fraction of net waste cost prevented — A lower value is rejected before calculation.

Prevention scenario rate maximum

preventionScenarioRate ≤ 1 decimal fraction of net waste cost prevented — A higher value is rejected before calculation.

• All inventory, sales, cost, target, capacity and cash values are supplied by the user.
• Money inputs use one consistent ex-tax currency basis and records refer to the same cohort or planning period.
• The engine retains raw precision; display formatting never feeds back into calculation.
• No jurisdiction, provider fee, industry benchmark or current policy value 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.

• Waste categories must be mutually exclusive for the measured cohort.
• Replacement sales hold the entered contribution rate constant and are not a sales forecast.
• The prevention rate is an owner scenario; the planner does not estimate operational achievability.

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.

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.

1. 2026-07-31: Initial public release of the planner and methodology after pre-launch calculation, content, source and interaction review.