BMI Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Biology, Medicine & Health

Tranche

calibration-1

Evidence ID

offline/source boundary

Ledger rows

1

No ledger note is attached.

Review findings

The arithmetic formula is standard, but the instrument needs an explicit population scope and exact category mapping before release. The existing honest label is appropriate: BMI is an educational screening estimate, does not distinguish fat from muscle, and is not medical advice.

Formula and scope findings

• BMI = mass in kilograms divided by height in meters squared is the standard adult BMI formula and is correct after unit conversion.
• The specification does not define the exact WHO category thresholds or whether categories apply to adults only; pediatric BMI requires age- and sex-specific percentiles rather than fixed adult bands.
• The formula field does not explicitly state the required conversion from pounds to kilograms and centimeters/inches to meters.

Unit assumptions

• Weight in kilograms is used directly; weight in pounds is converted using 1 lb = 0.45359237 kg.
• Height in centimeters is converted using 1 cm = 0.01 m; height in inches is converted using 1 in = 0.0254 m.
• Test categories assume adult WHO bands: underweight <18.5, normal 18.5-<25.0, overweight 25.0-<30.0, obesity >=30.0.
• BMI is treated as a screening index, not a direct measure of body-fat percentage or health status.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The hazard tests expose undefined behavior for zero height, a physically invalid but arithmetically defined zero-weight boundary, and a severe unit-convention ambiguity. The calculator must reject zero height and require unambiguous units; it should also validate nonpositive body measurements.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "weight": 70,
    "weight_unit": "kg",
    "height": 175,
    "height_unit": "cm"
  },
  "expected_outputs": {
    "BMI": 22.8571428571,
    "WHO_category": "Normal"
  },
  "working": "Height: 175 cm x 0.01 m/cm = 1.75 m. Height squared: 1.75 x 1.75 = 3.0625 m². BMI: 70 kg / 3.0625 m² = 22.8571428571. Since 18.5 <= 22.8571428571 < 25.0, category = Normal."
}

Related workflows

Sources and evidence

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

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche2/batch10-output.jsonl
• BOUNDARY_HAZARD_CATALOG.json