A standard drink and a unit of alcohol both measure pure alcohol, just in different sizes. A US standard drink contains 14 grams, a UK unit 8 grams and an Australian standard drink 10 grams. One US drink therefore equals 1.75 UK units or 1.4 Australian standard drinks, and each country's drinking guidance is written in its own measure.
That matters whenever you compare advice, read a study or count drinks from a label made for another market. Below are the official definitions, formulas, worked examples and current guidance for men.
How many grams of alcohol are in a standard drink?
Each system counts pure alcohol (ethanol), but the size of one counted drink differs by country.
| Country | What one drink is called | Pure alcohol in one | Current guidance for men |
|---|---|---|---|
| US | Standard drink | 14 g | No number; "consume less alcohol" |
| UK | Unit | 8 g (10 ml) | Not more than 14 units a week regularly |
| Australia | Standard drink | 10 g | No more than 10 a week and 4 on any one day |
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) defines a US standard drink as any beverage containing 0.6 fl oz or 14 grams of pure alcohol. Its examples are 12 fl oz of regular beer at about 5% alcohol, 5 fl oz of table wine at about 12%, and a 1.5 fl oz shot of distilled spirits at about 40%.
The NHS states that one UK unit equals 10 ml or 8 g of pure alcohol.
In Australia, the Food Standards Code defines a standard drink as the amount of a beverage containing 10 grams of ethanol measured at 20°C.
How do I calculate units of alcohol?
The NHS formula for UK units is: strength (ABV) × volume (ml) ÷ 1,000 = units. ABV, or alcohol by volume, is the percentage printed on the label.
The NHS works one example itself: a pint (568 ml) of strong lager at 5.2% gives 5.2 × 568 ÷ 1,000 = 2.95 units. Its own table rounds that to 3 units, and lists a 175 ml standard glass of 12% wine as 2.1 units and a 25 ml single measure of 40% spirits as 1 unit.
To turn units into grams, multiply by 8, because the NHS defines one unit as 8 g; that figure is rounded, so the result is approximate. The Australian and US columns below were calculated from pure alcohol instead: milliliters × ABV ÷ 100 × 0.789 gives grams, which you then divide by 10 for Australian standard drinks or by 14 for US standard drinks.
How do you calculate Australian standard drinks?
The Australian formula uses volume in liters. The Northern Territory's Liquor Act 2019 sets out the formula: standard drinks = volume in liters × ABV × 0.789. The Act notes that 0.789 represents the specific gravity of ethyl alcohol, which converts a volume of alcohol into grams.
The Act's own example is a 250 ml glass of 6% wine: 0.25 × 6 × 0.789 = 1.18 standard drinks.
The Food Standards Code also requires a statement of the approximate number of standard drinks on beverages containing more than 0.5% alcohol by volume, accurate to the first decimal place for containers holding 10 or fewer standard drinks.
Standard drink vs unit of alcohol: worked examples
The table below calculates common drinks three ways. UK units use the NHS formula. Australian standard drinks use the Liquor Act formula. US standard drinks take the Australian figure, convert it to grams (× 10) and divide by 14. All values are rounded to one decimal place.
| Drink | UK units | Australian standard drinks | US standard drinks |
|---|---|---|---|
| Pint of beer, 568 ml at 5.2% | 3.0 | 2.3 | 1.7 |
| Pint of beer, 568 ml at 3.6% | 2.0 | 1.6 | 1.2 |
| Can of beer, 375 ml at 4.8% | 1.8 | 1.4 | 1.0 |
| Glass of wine, 175 ml at 12% | 2.1 | 1.7 | 1.2 |
| Bottle of wine, 750 ml at 13% | 9.8 | 7.7 | 5.5 |
| Spirit measure, 25 ml at 40% | 1.0 | 0.8 | 0.6 |
Because the UK unit is the smallest measure and the US drink the largest, the same glass always gives its highest count in UK units.
The NIAAA notes that a 12-ounce bottle of beer at 10% alcohol contains two US standard drinks, not one.
What is the weekly alcohol limit for men?
Each country frames its guidance differently, and neither the UK nor the Australian advice calls any level of drinking completely safe.
UK. The UK Chief Medical Officers' guideline applies to both men and women: to keep health risks low, it is safest not to drink more than 14 units a week on a regular basis. If you regularly drink that much, it is best to spread it evenly over 3 or more days. The guideline adds that there is no level of regular drinking that can be considered completely safe in relation to some cancers. Fourteen units is 112 g of alcohol a week (14 × 8 g).
Australia. The national guidelines, as summarized by healthdirect, recommend that healthy adults have no more than 10 standard drinks a week and no more than 4 standard drinks on any one day. That is 100 g a week and 40 g in a day. Healthdirect also states that no amount of alcohol can be considered completely safe.
US. The Dietary Guidelines for Americans, 2025 to 2030 give no daily or weekly number. The alcohol section, headed "Limit Alcoholic Beverages", says to "consume less alcohol for better overall health." It lists people who should avoid alcohol completely: pregnant women, people recovering from alcohol use disorder or unable to control the amount they drink, and people taking medications or with medical conditions that can interact with alcohol. People with a family history of alcoholism are told to be mindful of their drinking.
For a US benchmark, the NIAAA's definition of heavy drinking for men is five or more drinks on any day or 15 or more a week. That is a threshold for heavy drinking, not a safe allowance.
How does alcohol affect sleep?
Healthdirect lists insomnia, meaning difficulty falling asleep or staying asleep, among the symptoms people may notice when they drink too much. If you fall asleep easily after drinking and then wake in the early hours, read waking up at 3 a.m. for how evening alcohol can change the second half of the night.
Checks for counting your own drinks
1. Keep the strength with the volume.
A pint, a glass or a can is not a measure of alcohol until you know the ABV. Read it from the label or menu, because strengths vary between products.
2. Use the label in Australia.
Australian packaged drinks above 0.5% alcohol must state the approximate number of standard drinks, which is quicker than doing the arithmetic yourself.
3. Measure your home pour once.
The NHS lists a large 250 ml glass of 12% wine as 3 units, against 1.5 units for a small 125 ml glass. Pour your usual glass into a measuring jug once and you will know which you actually drink.
4. Convert before you compare.
A study or app from another country may count in its own measure. Convert to grams first, then to your local measure.
5. Count the week, not just the night.
The Australian guidance adds a daily cap of 4 standard drinks. The UK Chief Medical Officers warn that one or two heavy drinking episodes a week increase the risk of death from long term illness and from accidents and injuries, so a weekly total packed into one night is not equivalent.
When should you talk to a doctor about drinking?
Talk to a doctor if you are regularly above your country's guidance, if you want to cut down and cannot, or if you need a drink in the morning to get going. Healthdirect lists these among the signs you may be drinking too much, alongside cravings, needing more to feel the same effect and drinking that affects relationships or work.
Healthdirect also notes that your doctor can help you manage any withdrawal symptoms and suggest support services. If you may be physically dependent on alcohol, get medical advice before stopping suddenly; the NHS alcohol support page warns that stopping overnight can be harmful. Hallucinations, severe tremors or seizures during withdrawal need emergency help: call 911, 999 or 000. In the US, start with a primary care physician; in the UK or Australia, a GP.
Bring an honest weekly total in grams or your local measure. It also helps with abnormal blood tests: alcohol is one of the causes doctors consider for elevated liver enzymes and high ferritin. If you keep a home blood pressure log, note drinking days in it too.
Frequently asked questions
How many grams of alcohol are in a standard drink?
It depends on the country. A US standard drink contains 14 grams of pure alcohol, an Australian standard drink contains 10 grams, and a UK unit contains 8 grams. So one US drink equals 1.4 Australian standard drinks or 1.75 UK units. Always check which system a label, app or study uses before comparing.
How many units are in a pint?
It depends on the strength. Using the NHS formula, a 568 ml pint at 3.6% contains about 2 units, and a pint at 5.2% contains 2.95 units, which the NHS rounds to 3. Multiply the ABV by 568 and divide by 1,000 to calculate any pint yourself.
How many standard drinks are in a bottle of wine?
A 750 ml bottle of 13% wine contains about 7.7 Australian standard drinks using the Liquor Act formula. The same bottle is about 9.8 UK units and about 5.5 US standard drinks. Stronger wine contains more, so check the ABV, and in Australia read the standard drinks figure printed on the label.
What is the weekly alcohol limit for men?
In the UK, men and women are advised not to drink more than 14 units a week regularly, spread over 3 or more days. Australian guidance is no more than 10 standard drinks a week and 4 on any one day. The 2025 to 2030 US Dietary Guidelines give no number and advise consuming less alcohol.
How do I calculate units of alcohol?
Multiply the strength (ABV) by the volume in milliliters, then divide by 1,000. A 175 ml glass of 12% wine gives 12 × 175 ÷ 1,000 = 2.1 units. Multiply units by 8 for approximate grams, then divide by 10 for Australian standard drinks or by 14 for US drinks.
The short version
A US standard drink is 14 g of alcohol, a UK unit 8 g and an Australian standard drink 10 g, so the same drink gives three different counts. Use the NHS formula for units and the Liquor Act formula, or the label, for Australian standard drinks. UK guidance is 14 units a week, Australian guidance is 10 standard drinks a week and 4 a day, and the current US guidelines simply say drink less.
This article is general education, not medical advice. It does not replace your own physician.
