Alcohol Unit / Standard Drink Counter mechanism

Model scope

The UK arithmetic formula is sound under the stated unit assumptions. The specification is not complete for US standard drinks or weekly guideline comparisons because the US conversion formula, ethanol-density assumption, jurisdiction, threshold, and accumulation period are missing.

• The UK formula is correct when Volume is in mL and ABV% is expressed as a numeric percentage: UK units = Volume_mL × ABV% ÷ 1000.
• The US formula is incomplete: 14 g is the definition of one US standard drink, but the specification does not provide the conversion from beverage volume and ABV to grams of ethanol. A density assumption is required, such as ethanol density = 0.789 g/mL.
• UK units and US standard drinks are different measures and must not be presented as interchangeable.
• The claimed weekly total requires a time period, accumulated consumption inputs, country or jurisdiction, and a specified guideline threshold. None is defined.
• The input field 'volume' is ambiguous unless its unit is explicitly constrained to mL or converted before calculation.
• ABV% is ambiguous unless the interface requires percentage points such as 5, rather than a fractional value such as 0.05.

Units and conventions

• Volume is entered in millilitres.
• ABV% is entered as a numeric percentage: 5 means 5% ABV; internally it is divided by 100.
• UK units are calculated as millilitres of pure ethanol divided by 1000.
• US standard drinks use 14 g of pure ethanol per drink.
• The test-vector US conversions assume ethanol density of 0.789 g/mL: pure_ethanol_g = pure_ethanol_mL × 0.789.
• The weekly guideline cannot be evaluated without a specified country, guideline source, time period, and threshold.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "volume_ml": 500,
    "abv_percent": 5,
    "unit_system": "UK and US"
  },
  "expected_outputs": {
    "uk_units": 2.5,
    "us_standard_drinks": 1.4089285714,
    "pure_alcohol_ml": 25,
    "pure_alcohol_g": 19.725
  },
  "working": "Pure alcohol = 500 × 5 ÷ 100 = 25 mL. UK units = 25 ÷ 1000 = 2.5. Pure alcohol mass = 25 × 0.789 = 19.725 g. US standard drinks = 19.725 ÷ 14 = 1.4089285714."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The extreme-magnitude vector produces Infinity through JavaScript floating-point overflow, and the US branch is not uniquely computable from the supplied formula without an ethanol-density assumption. ABV notation also permits a factor-100 convention error unless the input representation is explicit.

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-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json