How many standard drinks to .05?

Anyone licensed to operate a vehicle in Australia should know how many standard drinks it would take to reach 0.05. This seemingly innocent decimal should trigger a panic button response in drivers. After all, 0.05 is the legal limit of alcohol content in the bloodstream in Australia, and the consequences of getting caught are getting tougher and tougher as drink driving statistics show little improvement with each passing year.

Whether or not you are familiar with the legal impairment limit, it is crucial that you are responsible for your own personal tolerance level. After all, many people are incapable of operating a vehicle even if their alcohol breath tester reports blood alcohol content (BAC) below 0.05%. As such, they can still be arrested for compromising the safety of other people in the immediate vicinity.

Understanding your own limit begins with eradicating your mind of any clichés you’ve heard before, and know this:

Intoxication begins with just one drink.

For many people, this drink could very well have the lowest alcohol concentration on the market. But before we figure out how many standard drinks it would take to reach .05, we must start with understanding what’s a standard drink.

Check out our infographic below, or scroll down below for further explanation!



Step 1:


In Australia, a standard drink is one that contains 10 grams (about 12.5ml) of alcohol.

For other countries, this may be different. For example, in the UK, the standard is 8 grams (10ml) of alcohol.

So if you’re in Australia, just remember the magic number – 12.5.


Step 2:


Alcoholic beverages include a label noting the percentage of alcohol by volume (e.g. 5%). Therefore, to calculate how many standard drinks a beverage has would involve some simple math.

For example:

A 375ml bottle of mid strength beer (2.7% alcohol) = 375 x 0.027 = 10.12ml alcohol
10.12ml / 12.50ml = 0.81 standard drinks.

A 150ml glass of wine (11.5% alcohol) = 150 x 0.115 = 17.25ml alcohol
17.25ml / 12.50ml = 1.38 standard drinks.


Step 3:


After you’ve calculated how many standard drinks your beverage contains, you can start to estimate your own BAC and figure out how many drinks it would take to reach .05.

Remember that there are many factors that affect blood alcohol level (BAC) so you will have to test out the methods below to get an estimation. Also, note that even if someone else drinks the same drinks as you, it doesn’t mean that they will have the same BAC as you!

If you don’t have an alcohol breath tester to test your alcohol level, there are other estimation methods to know how many standard drinks it would take to reach .05… here are the most common ones.





The more you drink, the more drunk you feel. You may notice feeling more noticeable effects of alcohol on the body the more you drink. This may include mood swings, slurred speech, less inhibition, and worst of all, unsound judgement (I’m sure many of us have woken up the next day thinking, “why did I do that?!”).

The obvious thing to do is to not get behind a wheel and drive, but catch a cab home or hitch a ride from someone sober. But that decision isn’t that easy when you’re already not thinking too clearly.

So that said, self-assessment is the poorest method of calculating your BAC.



The general rule of thumb is that 2 standard drinks in the first hour will raise your BAC to 0.05%, and 1 standard per hour thereafter will maintain that level.

To do a quick calculation of whether you are over 0.05% BAC, simply take the number of hours since your first drink and add 1 to it. This is the number of standard drinks that you could safely have in that period.

Then calculate the number of standard drinks that you actually had, and compare the two results.

This method seems easy enough, and is free and convenient, too. But not all drinks are equal. Wine, beer and spirits all have varying alcohol concentrations, and the strength of a mixed drink can fluctuate radically based on who is doing the mixing.

When combined with poor drunken judgement, it makes calculating your BAC based on the number of drinks per hour extremely inaccurate.




With access to the web and smartphone apps, there’s little excuse to be uninformed about monitoring blood alcohol content (BAC).

There are, after all, a plethora of free resources geared towards helping consumers calculate their BAC levels.

These sites and apps have BAC calculators and charts that are very user friendly and make calculations based off a series of step-by-step questions. These questions usually include your age, gender, weight, alcohol strength, and alcohol consumption.

However, complete reliance on BAC calculators and charts is not a safe and reliable strategy. In fact, it could give a very inaccurate calculation as it omits important factors that affect blood alcohol level (BAC) and other medical-related information. For example, your metabolism, drug interactions and food consumption prior to the test can have a profound effect on the measurement.

So BAC calculators and charts may give you what seems like an accurate BAC estimation, but can in fact be totally off the mark.




It is a good idea to invest in a good alcohol breath tester (or an Andatech breathalyzer) if you are a regular drinker.

There can’t be enough emphasis on the quality of a device. After all, a 0.01% discrepancy in BAC detection accuracy can spell the difference between life, death, injury, or a hefty fine and prison sentence.

Many people purchase cheap brands of breathalysers for convenience. Usually, it’s because they are readily available at many convenience stores and gas stations. However, such devices usually employ antiquated technology. Such old technology may yield less accurate results than the readings achieved by law enforcement.

Andatech breathalyzers give consumers the best of both worlds; the latest fuel cell sensor technology for optimal readings packaged in a lightweight device. They work by measuring your breath alcohol level, which is related to your blood alcohol level. It then provides a digital reading for you in BAC format.

A breathalyser is the most reliable solution that takes a measurement directly from your breath sample. More importantly, it is not based on estimations and calculations of standard drinks and hours passed. Although not as accurate as a blood test, there is no other method that is as fast, convenient and reliable for an immediate alcohol breath test.

So now that you know about the different ways to find out how many standard drinks to .05, you can be more informed the next time you’re out drinking.

Whether you’re drinking one standard drink or two, remember that a wide range of factors influences your BAC. Therefore, if you drink, it’s best not to drive. If you want to be extremely sure, invest in a quality breathalyser or breath tester and check yourself before the cops test you.




Vivien Mah

Vivien Mah

Vivien is a Digital Marketing specialist with a background in psychology and communications, and a passion for educating readers and unraveling complexities behind difficult topics through extensive research. Apart from sharing her love for infographics, she also posts regularly on new products, announcements, media mentions and the latest news.


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