Source: https://guthlabs.ai/docs/instruments/emergency-fund-sizer/implementation/

instrument implementation / implementation-contract

# Emergency Fund Sizer implementation

A source-bound implementation contract for Emergency Fund Sizer; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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

[01**Overview**](<https://guthlabs.ai/docs/instruments/emergency-fund-sizer/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/emergency-fund-sizer/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/emergency-fund-sizer/qualification/>)

## 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`