Metabolic Equivalent (MET) / Activity Energy Calculator mechanism

Model scope

The core formula is standard for gross energy expenditure, but the instrument needs an explicit duration unit, a versioned MET lookup convention, input constraints, and an honest gross-versus-net label. The fourth test vector is deliberately corrected in its working: 8.0 × 3.5 × 75 / 200 = 10.5 kcal/min, so 1 hour produces 630 kcal.

• The formula kcal/min = MET × 3.5 × weight(kg) / 200 is the standard population-average estimate for gross energy expenditure, assuming 1 MET = 3.5 mL O2/kg/min and approximately 5 kcal/L O2.
• The specification does not state whether the result is gross calories or net/active calories. Net expenditure is commonly estimated as (MET - 1) × 3.5 × weight(kg) / 200, so the output label must explicitly say gross or net.
• The duration unit is unspecified. Because the formula produces kcal/min, duration must be explicitly supplied or converted to minutes.
• The activity-MET lookup and activity-name mapping are unspecified; the instrument needs a defined Compendium table version and behavior for activities absent from the table.

Units and conventions

• MET is dimensionless and represents the activity's gross metabolic rate relative to resting metabolism.
• Weight is body mass in kilograms.
• The formula output is kilocalories per minute.
• Duration is converted to minutes before multiplication; one hour equals 60 minutes.
• The 3.5 mL O2/kg/min MET convention and approximately 5 kcal per liter of oxygen convention are assumed.
• Expected outputs below are gross kcal, not net active kcal.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "activity": "Walking at 3.0 mph",
    "met": 3.5,
    "weight_kg": 70,
    "duration_min": 30
  },
  "expected_outputs": {
    "kcal_per_min": 4.2875,
    "total_kcal": 128.625
  },
  "reference_data": {
    "activity": "Walking, 3.0 mph",
    "met": 3.5,
    "source_convention": "widely tabulated standard value; Compendium of Physical Activities, 2011 update (Ainsworth et al.)"
  },
  "working": "MET × 3.5 × weight / 200 = 3.5 × 3.5 × 70 / 200. First, 3.5 × 3.5 = 12.25. Then 12.25 × 70 = 857.5. Then 857.5 / 200 = 4.2875 kcal/min. Total = 4.2875 × 30 = 128.625 kcal."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The extreme-magnitude vector causes floating-point overflow, and the duration field has an unresolved unit ambiguity that can change the result from 183.75 kcal to 11025 kcal for the same numeric input.

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-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json