Table of Contents

What is EWAC?

Alcohol is responsible for 5% of the global burden of ill health, yet individuals are not always aware of how much alcohol they drink, and whether this is likely to damage their future health.

EWAC stands for Estimated Weekly Alcohol Consumption. It can be measured using a short questionnaire known as the Extended AUDIT-C made up of three items measuring

  • quantity
  • frequency and
  • intensity of alcohol use.

This questionnaire is commonly used by doctors and nurses in health care services across the world.

The EWAC is calculated by adding the product of quantity by frequency to the intensity of alcohol use.

The result is provided both in

  • UK alcohol units (10ml or 8g of pure alcohol)
  • grams of pure alcohol

Its intended purpose is to monitor health and wellbeing, as well as to provide medical education.

Try it yourself using the EWAC Web App

How reliable is it?

A team of researchers validated EWAC in a random sample of over 15,000 individuals aged 16 years or more in England, designed to be representative of English households. EWAC was compared with a ‘gold standard’ alcohol interview schedule known as the ‘Graduated-Frequency questionnaire’.

The study underwent independent peer review before being published in an academic journal.

Read the study report (open access)

The study found that EWAC could be reliably presented as an interval of plus or minus 50%. Such an interval contains the ‘gold standard’ for 58% of individuals. But it is important to know that the ‘gold standard’ contains error of its own, so the interval will in fact be accurate for a very wide majority of individuals.


EWAC was developed by a team of researchers at the University of Southampton and University College London.

This research was supported by the Medical Research Council, the NIHR School for Public Health Research, and the NIHR Public Health Research Programme.

The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.