How much can someone drink and stay below a 0.05% Blood Alcohol Concentration (BAC) level?

blood alcohol concentration (BAC) level of 0.05% means that there are 0.05 grams of alcohol in every 100ml of blood. There is no level of drinking which guarantees that a person’s BAC will stay below 0.05%. Age, body size, gender, and a range of other factors can affect the rate at which alcohol is absorbed and metabolised when you drink. Everyone is different, and two people can drink the same amount of alcohol but have different levels of alcohol in their bloodstream. However, drinking less than one standard drink per hour should keep most people’s BAC below 0.05%, as the average rate at which alcohol is metabolised is one standard drink per hour.

Source: National Health and Medical Research Council (NHMRC) (2009). Australian guidelines to reduce health risks from drinking alcohol.

Blood Alcohol Concentration (BAC): A commonly used measure of alcohol intoxication. It refers to the amount of alcohol present in the bloodstream. For example, a BAC of 0.05% means that there are 0.05 grams of alcohol in every 100 millilitres of blood.

Standard Drink: A drink that contains 10 grams (or 12.5 millilitres) of alcohol.