Emergency Fund Sizer implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t4-092

Effect

Computation or source lookup only

Input and validation requirements

A zero current save rate produces division by zero for months_to-build and must be rejected or represented as undefined/infinite. The instrument also has a material unit-convention hazard: treating dollar inputs as cents changes every fund target by a factor of 100.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "monthly_essential_expenses": 2800,
    "target_months": 4,
    "current_save_rate": 700,
    "income_stability_flag": "stable"
  },
  "expected_outputs": {
    "low_fund": 8400,
    "high_fund": 16800,
    "target_fund": 11200,
    "months_to_build": 16
  },
  "working": "low_fund = 2,800 × 3 = 8,400. high_fund = 2,800 × 6 = 16,800. target_fund = 2,800 × 4 = 11,200. months_to_build = 11,200 ÷ 700 = 16 months."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json