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Scientific sources and references

All the medical information and blood alcohol calculations in DrinkMap are based on scientific research.

Warning

The estimates provided by this app are for guidance only and do not replace the use of an approved breathalyser. Many individual factors can affect your actual blood alcohol level, including:

  • Your personal metabolism
  • Your state of health
  • Medication
  • The contents of your stomach

If in doubt, don't drive and use an approved measuring device.

The Widmark formula

Our app uses the Widmark formula to estimate blood alcohol concentration. Developed by Erik M.P. Widmark, this formula is recognised and used in forensic medicine.

A: pure alcohol consumed (g) P: body weight (kg) r: distribution factor (0.7 men, 0.6 women) β: elimination rate (g/L per hour) t: time since you started drinking (h)

Main reference

  • Widmark, E.M.P. (1932). Die theoretischen Grundlagen und die praktische Verwendbarkeit der gerichtlich-medizinischen Alkoholbestimmung. Urban & Schwarzenberg, Berlin. en.wikipedia.org/wiki/Erik_Widmark

Studies on the formula

  • Jones, A.W. (2010). Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework. Forensic Science International, 200(1-3), 1-20. https://doi.org/10.1016/j.forsciint.2010.02.021
  • Gulberg, R.G. (2009). Variation in blood alcohol concentration following the last drink. Journal of Police Science and Administration, 13, 37-41.

Worked example

A drink contains about volume (mL) × ABV × 0.8 grams of pure alcohol. A 25 cL beer at 5% therefore contains 250 × 0.05 × 0.8 = 10 g of alcohol, one standard drink in France.

For a 75 kg man who drinks two of them: 20 / (0.7 × 75) ≈ 0.38 g/L at most. One hour later, with an elimination rate of 0.15 g/L per hour, the estimate drops to around 0.23 g/L.

This is still an approximation: absorption is not instantaneous and varies between people and with food.

Alcohol elimination rate

Our app uses a personalised elimination rate ranging from 0.085 g/L to 0.15 g/L per hour, depending on the user's drinking habits and gender.

Scientific references

  • Dubowski, K.M. (1985). Absorption, distribution and elimination of alcohol: Highway safety aspects. Journal of Studies on Alcohol, Supplement 10, 98-108. https://doi.org/10.15288/jsas.1985.s10.98
  • Jones, A.W. (2010). Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework. Forensic Science International, 200(1-3), 1-20.
  • Cederbaum, A.I. (2012). Alcohol metabolism. Clinics in Liver Disease, 16(4), 667-685. https://doi.org/10.1016/j.cld.2012.08.002
  • Frezza, M., di Padova, C., Pozzato, G., Terpin, M., Baraona, E., & Lieber, C.S. (1990). High blood alcohol levels in women: The role of decreased gastric alcohol dehydrogenase activity and first-pass metabolism. New England Journal of Medicine, 322(2), 95-99. https://doi.org/10.1056/NEJM199001113220205

Contact

For any question about our sources or methodology, you can contact us at: contact@drinkmap.fr