The drink driving limit in Australia
The short answer: if you hold a full licence, the legal limit is a blood alcohol concentration (BAC) below 0.05. If you're on a learner or P-plate licence, it's zero. Those two numbers apply in every state and territory — here's what they mean in practice.
The limits at a glance
Australia uses a two-tier system. Experienced full-licence drivers are allowed a small amount of alcohol in their system; newer and professional drivers are not. The table below sets out who falls into each category.
| Driver type | Legal BAC limit |
|---|---|
| Full (unrestricted) licence | Under 0.05 |
| Learner (L) drivers | 0.00 (zero) |
| Provisional / probationary (P) drivers | 0.00 (zero) |
| Supervising a learner driver | Under 0.05 (the supervisor must be under the full-licence limit) |
| Heavy-vehicle, bus, taxi & dangerous-goods drivers | 0.00 while working |
The 0.05 and zero limits are consistent nationwide, but the consequences of going over are set by each state and territory. That's where the numbers start to differ.
How many drinks is 0.05?
This is the question everyone asks, and the honest answer is: there's no safe number. The often-quoted rule of thumb from health authorities is that, to stay under 0.05, an average-size man can have no more than two standard drinks in the first hour and one standard drink each hour after that, while an average-size woman should stick to about one standard drink per hour (healthdirect).
But "average" is doing a lot of work in that sentence. Your actual BAC depends on your body weight, your sex, how much you've eaten, how quickly you drank, your fitness, any medication, and how tired you are. Two people can drink exactly the same and blow different numbers. As the Alcohol and Drug Foundation puts it, there is no way to know your precise BAC without testing — so any drinks-per-hour guide is a starting point, never a guarantee.
Penalties: it's not just about 0.05
Being over 0.05 isn't a single offence — the penalty scales sharply with how high your reading is. States group offences into ranges, and while the exact bands and fines vary, the structure is broadly similar. Using NSW as an example:
| Range | BAC | Typical consequences |
|---|---|---|
| Novice / special range | Above the zero or 0.02 limit for L, P and special-category drivers | Fine, licence suspension, demerit points |
| Low range | 0.05 to under 0.08 | Fine, immediate licence suspension, demerit points |
| Mid range | 0.08 to under 0.15 | Larger fine, longer disqualification, possible imprisonment, interlock |
| High range | 0.15 and over | Heaviest fines, long disqualification, imprisonment, mandatory alcohol interlock |
Across the country, mid- and high-range offences increasingly trigger a mandatory alcohol interlock — a breath-testing device wired to your ignition that stops the car starting if it detects alcohol. Immediate roadside licence suspensions for higher readings are now standard practice too. A first low-range offence is serious; a high-range one can end with a criminal record and time behind bars.
Random breath testing runs everywhere, all hours
Random breath testing (RBT) has been in place across Australia for decades and is one of the most effective road-safety measures ever introduced. Police can pull you over at any time, in any location, with no reason needed — highway, back road, suburban street, morning or night. The message from every state transport authority is the same: you can be breath-tested anywhere, anytime.
That "anytime" matters more than most people realise, because of what happens the morning after.
The morning-after trap
Your liver clears alcohol at a fixed pace — roughly one standard drink per hour, or about 0.015 of a BAC point every hour. Nothing speeds it up: not coffee, not a cold shower, not a big breakfast. If you finish a big night at 1am sitting around 0.15, you won't be back under 0.05 until well after 8am, and you may not hit zero until closer to midday.
Because RBT operates through the morning commute, "I slept on it" is one of the most common ways otherwise careful Australians end up charged with drink driving. If you've had a heavy session, the safest plan is to not drive the next morning at all — or to build in plenty of buffer and treat any estimate with caution.
How Drink Buddy helps
You can't control the RBT, but you can stay aware of roughly where you're at. Drink Buddy logs each drink as you go and shows a live BAC estimate and sobriety timer using the Widmark formula — the same method used in forensic and medical settings. It won't decide whether you can drive, but it makes the numbers visible, so "just a couple" doesn't quietly become five.
Frequently asked questions
What is the drink driving limit in Australia?
Under 0.05 for full-licence holders, and 0.00 (zero) for learner and provisional drivers. These limits apply in every state and territory.
How many drinks can I have and stay under 0.05?
As a rough guide, an average man might manage two standard drinks in the first hour then one per hour; an average woman about one per hour. But there's no safe number — individual factors mean the same drinks can put different people over the limit.
Is the limit the same in every state?
The 0.05 and zero limits are national. The penalties, suspension periods and exact BAC ranges differ between states and territories.
Can I be over 0.05 the morning after?
Yes. You clear only about one standard drink an hour, so after a heavy night you can still be over the limit into the next morning — and RBT runs at all hours.
What happens if I'm caught over the limit?
Expect a fine, demerit points and a licence suspension even for a low-range reading. Mid- and high-range offences add longer disqualifications, mandatory alcohol interlocks and, for serious cases, possible imprisonment.