A typical double in a bar holds about 2 US standard drinks, or roughly 28 grams of pure alcohol, though pour sizes vary by country and venue.
Why The Alcohol In A Double Matters
Many drinkers treat a double as a stronger version of their usual pour without thinking about how much pure alcohol sits in the glass. The word “double” also means different things in different bars and homes, which makes it easy to underestimate a night’s intake.
When you ask how much alcohol is in a double, you are actually asking two things: how big the pour is and how strong the spirit is. Once you know those two details, you can turn a double into standard drinks or units and see how it fits with health advice or legal limits.
What A Double Drink Actually Means
In most bars a double means two measures of spirits poured into the same glass. If a single shot is 1.5 ounces of 40 percent ABV spirit, a classic double holds 3 ounces, which comes out at about two US standard drinks of alcohol.
In the United Kingdom and many other places that follow similar rules, a single measure of gin, vodka, rum, or whisky is set at 25 or 35 millilitres. A pub must pick one size and use it consistently. A double measure is either 50 or 70 millilitres of spirit poured at the bar.
Home pours sit in their own category. People rarely measure exactly, and what one person calls a double might be closer to a triple for someone else. That is why it helps to understand the usual measures in bars before you start counting mixed drinks at home.
Typical Double Measures And Standard Drinks
The figures below assume a spirit strength of 40 percent ABV. Real drinks can differ, yet this table gives a useful starting point for judging how strong a double might be in different places.
| Setting Or Region | Typical Double Spirit Pour | Approx Pure Alcohol And Standard Drinks |
|---|---|---|
| US bar, classic double | 3 fl oz (about 89 ml) | about 28 g pure alcohol, around 2 US standard drinks |
| UK pub, 25 ml base | 50 ml | a little under 20 g pure alcohol, around 2 UK units |
| UK pub, 35 ml base | 70 ml | just under 30 g pure alcohol, close to 3 UK units |
| Australia or New Zealand bar | 60 ml | about 19 g pure alcohol, close to 2 local standard drinks |
| Canada bar | 3 fl oz (about 89 ml) | about 27 g pure alcohol, just under 2 Canadian standard drinks |
| European bar using 20 ml shot | 40 ml | about 13 g pure alcohol, near 1–1.5 standard drinks |
| Home free pour “small double” | 2.5 fl oz (about 74 ml) | about 23 g pure alcohol, near 1.5–2 standard drinks |
How Much Alcohol Is in a Double By Country
How much alcohol is in a double shifts with local definitions of a standard drink or unit, which use grams or millilitres of pure alcohol so people can compare different drinks.
United States
In the United States, public health agencies treat one standard drink as 14 grams of pure alcohol, and a 1.5 ounce shot of 40 percent spirit fits that rule. A 3 ounce double of the same spirit therefore holds about two standard drinks in a single glass. You can see this described in official standard drink sizes guidance.
Australia And New Zealand
Australia and New Zealand set one standard drink at 10 grams of pure alcohol. Bars often pour a 30 millilitre nip of spirit for a single and 60 millilitres for a double, so a double there counts as two standard drinks on local charts.
United Kingdom
In the United Kingdom the yardstick is the unit, equal to 10 millilitres of pure alcohol. A 25 millilitre single of 40 percent spirit counts as one unit, and a 50 millilitre double counts as two, while a 70 millilitre double based on a 35 millilitre single comes closer to three units. UK charity Drinkaware explains that spirits in pubs are sold in fixed single and double measures, with clear millilitre sizes for each serve on its guide to standard spirit measures.
Other Countries
Canada and several European countries use their own definitions that sit between these examples, yet many still treat a 1.5 ounce shot of 40 percent spirit as one standard drink. That means a true double usually falls around two standard drinks, even when the official numbers on paper shift a little.
Double Drink Alcohol Content Rules In Bars
Bars rarely improvise their spirit measures. In many countries they must follow weights and measures law that sets standard serving sizes for gin, vodka, rum, and whisky. Managers choose one legal single size, then set doubles as an exact multiple of that single.
Menus sometimes list doubles directly, yet staff might still default to singles unless you ask. In busy venues, staff often pour into a jigger and then tip the spirit into the glass with mixer or ice. Small differences in pour height seem minor but can change the alcohol in a double by several grams.
House policies also matter. Some venues pour stronger doubles as a selling point, while others pour slightly shorter doubles to keep prices down and reduce risk. Happy hour specials, oversized glassware, and free pour bartending can all push a drink above the number printed on the menu.
Factors That Change Alcohol In A Double
Two doubles that look the same can still hold different amounts of alcohol. Three details shape how strong your drink is: ABV, pour size, and dilution.
Many spirits sit at 40 percent ABV, yet some brands run nearer 37.5 percent while others go past 45 percent, so a double made with higher ABV always carries more pure alcohol than the same volume poured from a milder bottle.
Even where the law sets fixed single measures, staff can overpour or underpour, and a tall glass with a quick heavy pour can add more alcohol than you expect to what you think is a standard double.
Mixers and ice change taste and speed, not the amount of alcohol in the glass. A long drink with plenty of cola or tonic water may seem gentle while a short drink served neat or on the rocks often feels stronger, even though the double shot at the bottom stays the same.
Comparing A Double With Other Drinks
A double often feels like one drink in your hand, yet it rarely counts as one drink on a health chart. Turning your double into standard drinks helps you pace yourself through an evening.
In US terms, a 12 ounce beer at 5 percent ABV counts as one standard drink, while a 3 ounce double of 40 percent spirit holds about two. One double on its own lands in the same range as two bottles of regular beer.
Wine sits between beer and spirits. A 5 ounce glass of 12 percent wine counts as one US standard drink, yet large pours at home can climb to 8 or 9 ounces, which brings the total close to a full double in terms of pure alcohol, even though it arrives in a stemmed glass instead of a tumbler.
How A Double Stacks Up Against Common Servings
The next table translates a classic 3 ounce double of 40 percent spirit and typical UK doubles into standard drinks or units beside familiar servings of beer and wine. Values are rounded to keep the numbers simple.
| Drink Or Serving | Volume And Strength | Approx Standard Drinks Or Units |
|---|---|---|
| Double spirit, US style | 3 fl oz, 40 percent ABV | about 2 US standard drinks |
| Double spirit, UK 25 ml base | 50 ml, 40 percent ABV | about 2 UK units |
| Double spirit, UK 35 ml base | 70 ml, 40 percent ABV | close to 3 UK units |
| Regular beer | 12 fl oz, 5 percent ABV | about 1 US standard drink |
| Strong beer pint | 16 fl oz, 7 percent ABV | close to 2.5 US standard drinks |
| Table wine glass | 5 fl oz, 12 percent ABV | about 1 US standard drink |
| Large wine pour at home | 9 fl oz, 13 percent ABV | close to 2 US standard drinks |
How Doubles Count Toward Guidelines And Legal Limits
Once you know where a double sits in standard drinks, you can gauge how fast you move toward low risk drinking advice. Most public health agencies frame their guidance in weekly and daily caps plus at least a few alcohol free days.
In the US, health agencies treat one standard drink as 14 grams of alcohol and encourage adults who choose to drink to keep intake low across the week. In the UK, guidance talks about a weekly cap spread across several days, based on units instead of grams. Other countries use their own targets, yet the pattern is similar. A single double can take a large slice out of the suggested daily amount.
Legal limits for driving are a separate issue. Blood alcohol level depends on body mass, sex, drinking pace, and how much food you ate. Because a double often equals two or more standard drinks, a short run of doubles can push a person near or above legal driving limits faster than they expect.
Practical Tips For Ordering And Tracking Doubles
If you want a clearer answer to the strength of a double on any given night, start with a short chat at the bar. You are not being awkward by asking for serving details; you are simply choosing to know what is in your glass.
Ask what the bar uses as a standard single spirit measure and whether a double is exactly twice that size. Where singles and doubles appear on the menu, read the small print that shows millilitres or ounces for each pour, and glance at the spirit bottle to see the ABV.
Then give yourself a simple rule: treat one double as two drinks on your personal tally. Keep a quiet running total in your head or on your phone, and space out doubles with water, soft drinks, or food so your body has more time to process the alcohol.
At home, a small jigger or spirit measure keeps homemade doubles close to the figures used by health agencies. Guessing by eye tends to creep upward, while a cheap measure keeps pours steady from night to night.
Finally, plan your way home before the first drink instead of after the last double. Arrange a lift, taxi, or public transport in advance so you are never tempted to drive while your judgement is still under the influence of the alcohol in those doubles.