Breath Alcohol Calculator

How to Use

  1. Enter your breath alcohol reading in µg/100ml (UGL).
  2. Choose your preferred display unit:
    • mg/100ml Blood (MGL)
    • ‰ (Promille) Blood Alcohol Concentration (BAC)
  3. The calculator will instantly convert your reading into the selected unit.

Enter Breath Level in μg/100mL:

Please note

This calculator is for guidance only. Breath, blood and BAC conversions are estimates and should not be relied upon to determine whether you are legally fit to drive, fly or undertake safety-critical work.

Reference Limits (Breath Alcohol – UGL)

Limit Breath Alcohol (UGL)
Aviation Limit 9 µg/100ml
Network Rail Limit 13 µg/100ml
Scotland Drink Drive Limit 22 µg/100ml
England, Wales & Northern Ireland Drink Drive Limit 35 µg/100ml

Important

Alcohol affects everyone differently depending on factors such as body size, sex, food intake, metabolism and medication. The safest option is not to drive, fly or undertake safety-critical work after consuming alcohol, regardless of your reading. If you are unsure whether you are below the relevant legal or workplace limit, do not proceed.