Body Fat % (BMI-based, Deurenberg) 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

t2-050

Effect

Computation or source lookup only

Input and validation requirements

The plain arithmetic engine can return Infinity for extreme finite JavaScript inputs, and it produces a negative body-fat estimate at the zero boundary instead of rejecting nonphysical inputs.

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": {
    "BMI": 22,
    "age": 30,
    "sex": 0,
    "sex_encoding": "female=0, male=1"
  },
  "expected_outputs": {
    "body_fat_percent": 27.9
  },
  "working": "BF% = 1.20×22 + 0.23×30 − 10.8×0 − 5.4\n= 26.4 + 6.9 − 0 − 5.4\n= 33.3 − 5.4\n= 27.9%"
}

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-tranche2/tranche2-results.json