Your blood alcohol level is, unsurprisingly, the amount of alcohol circulating around your bloodstream. Your blood alcohol level is measured in grams of alcohol per hundred millilitres of blood.

The legal limit for your blood alcohol level (also known as blood alcohol concentration or BAC) in Australia depends on the category of driver you are. Experienced drivers are those who are over 18 and have been able to drive for three years but are not professional drivers. This category of driver is permitted a slightly higher blood alcohol level. Learner and probationary drivers, and professional drivers (e.g. those who are driving, taxis, buses, heavy vehicles or dangerous goods) have a lower blood alcohol limit.

The legal blood alcohol limit throughout MOST of Australia is “under 0.05” for experienced drivers (in other words, an experienced driver is permitted to have five grams of alcohol per 100 ml of blood). In most states of Australia, the permitted BAC for learner and probationary drivers is absolute zero, but in ACT and Western Australia, the maximum blood alcohol level is 0.02. For professional drivers, the permitted blood alcohol level is 0.02 in NSW and ACT, and zero for all other states.

The only guaranteed way to stay below the legal blood alcohol level is not to drink at all. However, you can keep a track of your likely blood alcohol level by watching the amount you drink. As a general rule of thumb, you can stay under the legal blood alcohol limit of 0.05 by drinking two standard drinks in the first hour of a “session” and one standard drink an hour after that if you are a man, and one standard drink per hour if you are a woman. This is only a general guideline, because body mass, body fat and the amount of food taken with drinks will also affect where your blood alcohol level will be after following these guidelines. A standard drink is one that contains 10 grams of alcohol.

If you are concerned that you will be nabbed for being over a blood alcohol limit of zero when you haven’t been drinking but have used mouthwash or eaten a dish that contains alcohol as an ingredient (e.g. as a marinade on meat), don’t worry. The BAC tests are designed not to pick this amount of alcohol up.
We hope that helps answer the question ‘What is What is a Blood Alcohol Level?’!

Back to Car Glossary