Trip Fuel Cost Calculator 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

t4-103

Effect

Computation or source lookup only

Input and validation requirements

A zero-MPG input causes division by zero and can produce undefined mathematical results or JavaScript Infinity. Negative distance also exposes an unresolved validation/convention issue because the raw formula returns negative gallons and cost.

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": {
    "trip_distance": 300,
    "distance_unit": "mi",
    "vehicle_mpg": 25,
    "fuel_price": 3.6,
    "price_unit": "USD/US gal"
  },
  "expected_outputs": {
    "gallons_needed": 12,
    "fuel_cost": 43.2
  },
  "working": "gallons_needed = 300 mi ÷ 25 mi/US gal = 12 US gal; fuel_cost = 12 US gal × $3.60/US gal = $43.20"
}

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