Technically speaking, a unit contains 10ml of pure alcohol. Due to the different types of drinks and strengths on the market, we need to have a standardised way to understand how each drink measures up against each other. It’s not uncommon for people to associate certain drink types with a problem. As an example, drinking 4 bottles of wine a week (one bottle being 14% ABV in a standard 750ml bottle size) equates to 42 units of alcohol per week. That’s roughly equivalent in units to drinking a one litre bottle of vodka per week. For some people the idea of drinking a litre of vodka a week is not something they can imagine themselves doing. But if we viewed the units alone, that is the same level of risk regardless of the drink type. So understanding units is important to help us understand our own level of risk and cut through any misconceptions.
Units are the standardised way in which we measure alcohol in the UK. Other countries use “standard drinks” which work in the same way to units. Once we’ve got a handle on understanding them, it can really help with keeping an accurate track of our alcohol intake. So, read on as we guide you through the basics of alcohol and units.
Why is it important to understand what a unit is?
Because of the variety in strength (also called ABV) and serving size of each alcoholic drink we may consume, the different combinations of alcohol in cocktails and mixers, as well as the choices we make around which drinks to consume – the amount of pure alcohol we end up consuming can vary a lot. Our weekly units can easily stack up - especially if we are not aware of what they really are. Units give us a way to measure the amount of pure alcohol we are consuming regardless of the drink type.
Why is it important to understand what a unit is?
Because of the variety in strength (also called ABV) and serving size of each alcoholic drink we may consume, the different combinations of alcohol in cocktails and mixers, as well as the choices we make around which drinks to consume – the amount of pure alcohol we end up consuming can vary a lot. Our weekly units can easily stack up - especially if we are not aware of what they really are. Units give us a way to measure the amount of pure alcohol we are consuming regardless of the drink type.
What are the guidelines when it comes to units?
The UK low-risk guidelines says that both men and women should have no more than 14 units per week, spread out over three or more days to keep their risk from alcohol low. If you’re pregnant, or trying to get pregnant, it’s safest to not drink alcohol to keep the risks to the baby low.
What does the weekly units total from the UK low-risk guidelines look like in reality?
Whilst the guidelines are useful as a starting point, at times, it can still be tricky to understand how 14 units translate to drinks. To help with this, we’ve put together this handy graphic.
This is what 14 units looks like in common alcoholic drinks:
Does 1 unit = 1 alcoholic drink?
No, one drink doesn’t equal one unit of alcohol, although this is a common mistake people can make. As we’ve covered above, things like the type of alcohol you’re drinking makes a huge difference to the total amount of alcohol you may end up consuming.
Just think of it this way, if we approached 14 units as 14 drinks per week, then this would produce a huge variety in the amount of alcohol consumed depending on the drinks that have been chosen. Remember, not all drinks are made equal.
Has the guidance changed on units over the years?
Yes, over the years, some things have changed around the way we explain units. Units can still be a bit confusing for many of us and this can partly be attributed to the way the information was presented in the past by UK health bodies. In times gone by, health professionals may have explained units like so:
- 1 unit = half a pint (3.5% ABV)*;
- 1 unit = single spirit (25ml / 40% ABV);
- 1 unit = glass of wine (125ml / 8% ABV).
The eagle-eyed amongst us may have noticed some problems with the older information above. Over time in the UK, serving sizes have changed, as well as the average ABV increasing. This means the drinks we consume may be larger and/or stronger than what we perceive.
For example, most average beers and lagers are in fact stronger than 3.5%, with some of the most popular UK lagers and beers sitting at around 4% ABV. Add into this, data that suggests most punters these days choose pints over halves, so a larger volume of alcohol. Plus, with the popularity of craft beers in recent times beer drinkers may find the range of ABV they end up drinking can go upwards of 8% ABV.
Can I get an example of how you’d calculate units for a specific drink?
Let’s use a 500ml can of super-strength lager to demonstrate how to calculate units:
%ABV x milliliters / 1000 = units
| %ABV x millilitres | = | 4000/ | = |
| 8% x 500ml | 1000 | 4 units |
In this example with a large super-strength lager, one can contains 4 units of alcohol.
Are there any shortcuts to help with working out units in drinks?
There are some shortcuts which can be helpful when it comes to calculating units, such as using round numbers. For example, the units in a litre of any drink will be the same as the ABV%. So, if we look at a 1 litre bottle of 40% ABV spirits, there are 40 units within that bottle. If you have a drink that is 500ml, the number of units is exactly half of the ABV%.
How do I approach figuring out the number of units in wine?
Working out the number in units can be a little complicated, and this is, in part, also down to the rise in ABV strength and larger serving sizes in bars, pubs and restaurants.
As you may have experienced yourself, standard servings in restaurants and bars are now medium glasses (175ml) and large glasses (250ml), over the smaller 125ml size. Historically, a bottle of wine on a table at a function would serve six guests with a 125ml serving each. Now, with the rise of larger glasses and servings, it can feel very normal to share one bottle over dinner with a friend or partner.
An additional factor to this is that most wines available to us in supermarkets and hospitality venues are well above 8% ABV, with an average of around 13% ABV and with some even upwards of 16% ABV! So, as you can see, already in terms of total units, we’re a long way off that historical idea of one glass of wine equalling one unit of alcohol.
To get around these complicating factors, we’d recommend using these more up-to-date examples instead:
- A large glass of red wine (usually around 14% ABV), being equal to around 3.5 units in one glass.
- A large glass of white wine (usually around 12% ABV) being equal to around 3 units in one glass.
However you approach it, it’s important to recognise that serving size and strength are the two key factors in your drink choices. If you feel like you’d like help calculating your units, the free Try Dry® app can help you with this.
How do I approach figuring out the number of units in spirits?
When it comes to understanding the amount of units in spirits, on most counts things are a little simpler, and a single serve does often equal one unit. When ordering spirits in hospitality venues in the UK, most bars will serve a standard 25ml single, however, it’s useful to aware that some do serve a large single of 35ml. It can be a good idea to check with the bartender what their standard is and ask for singles to help you keep track. As ever, for an extra helping hand calculating your units, download the free Try Dry® app.
How do I go about calculating units when drinking at home?
For a variety of reasons, it’s now fairly common to drink alcohol at home. Home pouring alcohol, often from larger bottles, is not as exact as a drinks pour in the bar. You could think about it this way, a standard single serving of alcohol is 25mls, or to put it another way, just 5 teaspoons’ worth of liquid. Many of us would struggle to measure this by eye and the tendency is to over-pour rather than less. Our top tip for if you’re drinking at home and would like to keep on top of your units consumption is to use a measuring cup or jug to keep track. If you’d like, you can easily pick up the serving measures used in pubs and bars from online retailers.
So, there you have it – your mini guide to understanding units of alcohol! It’s not always straightforward but calculating units correctly can be a brilliant (and important) tool to keep a handle on your drinking. Try to keep in mind the ABV% strength and the size of a drink as your starting point and remember you can always use our free tools to do all the heavy lifting for you, including our online Unit Calculator and our free Try Dry ® app, ‘Tips for Cutting Back on Alcohol’ WhatsApp channel, or check out our free four-week Try Dry® Anytime Cut Back challenge.
