What Counts as One Drink in the US, UK and the Nordics

You pour a glass of wine at home, fill it to where it looks right, and count it as one drink. Whether it is one depends on the glass, the wine and which country's health advice you go by. In health guidance a "drink" means a fixed amount of pure alcohol, and that amount differs between the US, the UK and the Nordic countries.

Here is what one drink means in each place, what it looks like in your glass, and how to count what you pour.

One drink is a weight of alcohol

Health authorities measure drinks in grams of pure alcohol. The water, sugar and bubbles around it don't count. A can of beer and a shot of vodka can hold the same amount of alcohol, so they count the same.

The catch is that each country picked its own size. A standard drink in the US holds about 14 grams of alcohol. A UK unit holds 8 grams. Sweden, Denmark and Finland use 12 grams, and Norway uses 12.8 grams. Two drinks in Chicago hold more alcohol than three units in Manchester.

The United States: 14 grams

The National Institute on Alcohol Abuse and Alcoholism (NIAAA) defines one standard drink as about 14 grams of pure alcohol. That is roughly:

• a 12-ounce (355 ml) can of regular beer at 5%
• a 5-ounce (148 ml) glass of wine at 12%
• a 1.5-ounce (44 ml) shot of spirits at 40%

NIAAA points out that these sizes often differ from what bars and people pour. A 12-ounce beer at 10% holds two standard drinks.

The United Kingdom: 8 grams

The UK counts in units. One unit is 10 ml, or 8 grams, of pure alcohol. The NHS gives these everyday examples:

• a single 25 ml measure of spirits at 40%: 1 unit
• a small 125 ml glass of wine at 12%: 1.5 units
• a pint of lower-strength beer at 3.6%: 2 units
• a pint of higher-strength beer at 5.2%: 3 units
• a large 250 ml glass of wine at 12%: 3 units
• a 750 ml bottle of wine at 13.5%: 10 units

Because a unit is small, UK numbers look bigger than American ones for the same evening. A large glass of wine is 3 units in London and about 1.7 standard drinks in New York.

Norway, Sweden, Denmark and Finland: about 12 grams

The Nordic countries use a measure between the two. Each has its own name for it.

Norway: alkoholenhet

Helsedirektoratet defines one alcohol unit as 15 ml of pure alcohol, which weighs 12.8 grams. That equals:

• 33 cl of beer, cider or alcopop at 4.5%
• 12.5 cl of wine at 12%
• 4 cl of spirits at 40%

Sweden: standardglas

Socialstyrelsen sets one standard glass at 12 grams of alcohol. That equals:

• 50 cl of folköl, the lighter beer
• 33 cl of starköl, regular strong beer
• 12 to 15 cl of wine
• just under 4 cl of spirits

Denmark: genstand

Sundhedsstyrelsen sets one genstand at 12 grams of alcohol. That equals:

• a 33 cl beer at 4.6%
• 12.5 cl of wine at 12%
• 4 cl of spirits at 40%

Finland: alkoholiannos

Finland's national treatment guideline puts one alkoholiannos at about 12 grams of alcohol. That equals:

• a 33 cl bottle of medium-strength beer or cider
• 12 cl of wine
• 4 cl of spirits

How to count what is in your glass

Labels give strength as ABV, the share of the drink that is alcohol. To find the alcohol in any drink:

1. Multiply the volume in ml by the ABV, then divide by 100. That gives ml of pure alcohol.
2. Multiply by 0.8 to get grams. The NHS figure of 10 ml to 8 grams uses the same ratio.
3. Divide by your country's size: 14 for a US drink, 8 for a UK unit, 12 for Sweden, Denmark and Finland, 12.8 for Norway.

Take a 175 ml glass of 13% wine. It holds 22.75 ml of alcohol, or about 18 grams. That is 1.3 US drinks, 2.3 UK units, or 1.5 Swedish, Danish or Finnish units. A 500 ml can of 5.5% lager holds 22 grams: about 1.6 US drinks, 2.75 UK units or 1.8 Nordic units. For UK units there is a shortcut from the NHS: ABV times ml, divided by 1,000.

Pours at home tend to run large. When US researchers asked drinkers to pour their usual drink at home and measure it, the average wine and spirits drinks held more alcohol than a standard drink. The average spirits drink held about one and a half. NIAAA's advice for this is short: measure drinks at home.

Why the size matters when you compare advice

Each country writes its drinking advice in its own measure, so the same number can mean different amounts. The UK's guideline of 14 units a week is 112 grams. Finland's THL treats more than 14 alkoholiannos a week as a health risk for men, a line at about 168 grams. Denmark's limit of 10 genstande a week works out at 120 grams.

US numbers need the same care. NIAAA defines heavy drinking for women as 8 or more drinks a week, which is 112 grams, the same as the UK's 14 units. For men it is 15 or more drinks a week, which is 210 grams.

So when an article, an app or a friend abroad talks about "two drinks a day", ask whose drinks they mean. Our guide to drinking guidelines by country puts the current advice side by side.

Putting your number to use

Once you know your real number, you can do something with it. Add up a normal week in your country's measure, then run it through the savings calculator to see what it costs you over a year and what cutting back would leave you with. The drinking self-check uses the ten questions of the AUDIT, the World Health Organization's screening test, and takes about two minutes.

If the total is higher than you guessed, the UK's chief medical officers suggest several drink-free days each week as a good way to cut down. Our plan for cutting back or quitting walks through the first steps. If you drink heavily every day, stopping suddenly can be dangerous. Talk to a doctor first.