Units and calories in rum

Rum is a spirit made from sugar cane juice or fermented molasses that comes in both white and dark varieties. It’s commonly used in cocktails and mixed drinks.

Like all spirits, rum has a high alcohol content. Legally, any rum sold in the UK must be at least 37.5% alcohol by volume (ABV).¹ That means 37.5% of the drink is pure alcohol – and if the ABV is higher, the percentage of alcohol will be higher too. 

To keep health risks from alcohol low, if you choose to drink, it’s important to stick to the UK Chief Medical Officers' (CMOs’) 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.²

Regularly drinking more than the low risk drinking guidelines increases your risk of developing a range of health problems including heart and liver disease, and seven types of cancer.³  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.⁴

How much alcohol is in rum?

Checking the ABV (alcohol by volume) of rum will tell you what percentage of the drink is made up of alcohol. For example, half of a single measure (25ml) of rum which has a 50% ABV 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 of pure alcohol – and the number of units you are drinking depends on the drink’s size and strength.

Pubs and bars usually serve spirits like rum in 25ml measures, about one unit of alcohol, or ‘doubles’ which is a 50ml measure and about two units of alcohol. 

And if you drink rum 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. If you drink rum at home, a good way to avoid accidentally pouring too much rum, and to keep track of your units, is by using an alcohol unit measuring cup.

How many calories are in rum?

Alcohol contains around seven calories a gram, almost as many as one gram of fat.⁵  A single (25ml) measure of 40% ABV rum can contain around 56 calories.⁶

And don’t forget that in a cocktail the mixer also adds to the overall calorie count. For example, a rum and coke can contain around 214 calories.⁷ Just like in other alcoholic drinks, these are ‘empty calories’ with no nutritional value, so don’t benefit your body in any way.⁸

Drinking rum, or any other alcoholic drinks, means you will be taking on extra calories on top of your food. And because alcohol also reduces the amount of fat your body burns for energy, drinking can lead to weight gain.⁹