Subsidy Phaseout One Income Band Tool

Description

Calculate subsidy phaseout one income band from explicit caller-supplied inputs.

A policy scenario makes eligibility bases, rates, thresholds, periods, and costs explicit. A calculated share or balance follows those assumptions. It does not select the governing policy or establish what caused an observed program outcome.

Calculate subsidy phaseout one income band from explicit caller-supplied inputs.

When to use this tool

Use it for subsidy phaseout one income band when the required inputs and conventions are already available.

How to use the tool and how it works

Enter income, lowerIncome, upperIncome, fullSubsidy. Use the stated units and boundary conventions.
Run the calculation. Correct any input error before interpreting a result.
Read retainedFraction, subsidy. Inspect any known, defined, inclusion, or boundary flags before interpreting numeric values.

Require nonnegative income and fullSubsidy with upperIncome>lowerIncome>=0. Calculate retainedFraction=(upperIncome-income)/(upperIncome-lowerIncome), clamp it to zero through one, and multiply by fullSubsidy.^[1]

Input field	Meaning and units	Accepted input
income	Income	Required. Finite number; minimum 0.
lowerIncome	Lower Income	Required. Finite number; minimum 0.
upperIncome	Upper Income	Required. Finite number.
fullSubsidy	Full Subsidy	Required. Finite number; minimum 0.

Output field	Interpretation	Returned shape
retainedFraction	Retained Fraction	Required. Finite number.
subsidy	Subsidy	Required. Finite number.

json

{
  "input": {
    "income": 150,
    "lowerIncome": 100,
    "upperIncome": 200,
    "fullSubsidy": 80
  },
  "output": {
    "retainedFraction": 0.5,
    "subsidy": 40
  }
}

Limitations and assumptions

The subsidy is full at or below the lower boundary and zero at or above the upper boundary. No current program rules, household assessment, or rounding convention is selected.
The field tables describe structural bounds; the mechanics also state cross-field requirements. Malformed input shapes, disallowed keys, and invalid domains cause input errors. Results must remain finite and within the declared output contract. A successful false flag or zero placeholder is distinct from an error.
Numeric arithmetic uses binary floating point. Exact comparisons have no hidden tolerance or decimal rounding; negative zero is exported as zero. Decimal-text integer operations retain the exactness specifically stated above.

Alternative or Complementary methods

For subsidy phaseout one income band, check the source records and the supplied rule before comparing the result with another method. Consult the applicable authoritative rule when deciding eligibility, legal timing, fees, or obligations.

References

Calculation and input contract: public-policy/subsidy-phaseout-one-income-band — tool.io

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