Units and calories in whisky
Find out how many units of alcohol and calories there are in whisky, and how that relates to the low risk drinking guidelines.
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Whisky is a strong alcoholic drink. Legally, any whisky (or ‘whiskey') sold in the UK must be at least 40% alcohol by volume (ABV).1 That means forty percent of the drink is pure alcohol - and if the ABV is higher, the percentage of alcohol is higher too.
In comparison beer is often around 5% ABV, so an average whisky is eight times stronger.
To keep health risks from alcohol low, if you choose to drink, it’s important to stick to the UK Chief Medical Officers' low risk drinking guidelines. That means no more than 14 units a week, spread over three or more days, with several drink-free days - and no bingeing.
Drinking alcohol also causes at least seven types of cancer, including breast, bowel, mouth and throat cancers.2 The risk of developing these types of cancer starts to increase even at low levels of drinking - so the less you drink, the more you reduce your risk.
Checking a whisky’s ABV (alcohol by volume) tells you what percentage of the drink is made up of alcohol. The higher the percentage, the more alcohol there is - for example, half of a 50% ABV whisky is pure alcohol.
A good way to keep track of how much you’re drinking is to know how many units of alcohol are in your drink. One unit of alcohol is 10ml (ten millilitres) of pure alcohol – and the number of units you are drinking depends on the drink’s size and strength.
Drinking more than 14 single measures of whisky in a week would mean you are drinking more than the UK low risk drinking guidelines.
Pubs and bars used to commonly serve spirits like whisky in 25ml measures - that’s about one unit of alcohol per measure of whisky. But these days many pubs and bars have switched to 35ml or 50ml measures – meaning you might be having a lot more alcohol without realising.
If you drink whisky as part of a mixed drink or a cocktail, it’s worth remembering there can be several measures – even if the drink doesn’t taste particularly strong. And if you drink at home, a good way to avoid accidentally pouring too much and limit how many units of alcohol you have is by using a measuring cup.
Alcohol contains around seven calories a gram, almost as many as pure fat. So, because whisky contains a lot of alcohol, it’s high in calories too. A typical 25ml single of whisky can contain 61 calories.
As well as having a high calorie content on its own, if you mix whisky with a sugary mixer like lemonade or ginger beer, you could end up drinking far more calories than you realise.
A whisky with a 48% ABV contains 1.2 units per single (25ml) measure, compared to one unit in 25ml of a 40% whisky. When ordering a drink, or buying a bottle, always be sure to check the alcohol content so you can track your units accurately.
Units and calories in whisky mount up quickly, especially when consuming in quantities over a 25ml single measure. Stick to singles when you’re out, and buy a measuring cup from the Drinkaware shop for drinking at home so you can be sure exactly how much you’re drinking.
Cocktails can often be ‘free poured’ by eye or served using larger measures than a standard 25ml single so it can be difficult to know how much alcohol you’re really drinking. Ask the bartender to tell you how they’re making your drink so you can keep track of your units.
Try an alcohol-free mocktail instead.
Last Reviewed: 16th February 2023
Next Review due: 16th February 2026