Legal i

How many can I have before driving?

Summer is approaching and with it comes a host of social and sporting events during which we typically find the number of motorists charged with offences increases. It becomes harder to resist that “one pint after work” when you walk outside to blazing sunshine and the overall mood is far more joyous than on a usual grey Tuesday. 


We are often asked how many drinks someone can have before driving, and the truth is that it is a very difficult question to answer with any certainty. Every person will process alcohol differently depending on their age, gender, height, weight and individual metabolism. You and a pal could both drink five pints with only one of you still being over the limit a few hours later. 


The main thing to remember is that there is a huge difference between feeling alright to drive and actually being safe to drive, and we help many clients who have felt absolutely fine at the time of driving, but were still nevertheless found to be over the legal limit. This is largely due to individual tolerance to the effects of alcohol, but it is not necessarily an effective indicator as to whether you are over the legal limit. 


The internet is filled with websites and mobile apps that offer to calculate your alcohol level and help you stay safe. Whilst these may be good as an estimate, they should never be taken as 100 per cent accurate due to the large number of variables involved. And you often hear conversations from motorists talking about units of alcohol and how many they can have, without really understanding how it works, so hopefully this information will help you make your own, more informed calculations about whether you are actually safe to drive. 


In the table, you can see what drinks contain in terms of alcohol units. Each unit roughly equates to 10 millilitres of alcohol, and the legal limit is 35 millilitres of alcohol per 100 millilitres of breath. The average person will metabolise 1 unit of alcohol each hour. 


Beverage Units

Small glass of wine (ABV 12%, 125ml) 1.5
Standard glass of wine (ABV 12%, 175ml) 2.1
Large glass of wine (ABV 12%, 250ml) 3
Pint of lager/beer/cider (ABV 3.6%) 2
Pint of lager/beer/cider (ABV 5.2%) 3
Bottle of lager/beer/cider (ABV 5%, 330ml) 1.7
Can of beer/lager/cider (ABV 4.5%, 440ml) 2
Alcopop (ABV 5.5%, 275ml) 1.5
Single shot of spirit (ABV 40%, 25ml) 1


So, for example, the amount of alcohol in three small glasses of wine would place you over the limit, as you would consume 4.5 units, which roughly equates to 45 millilitres of alcohol. But that does not take into account the passage of time, so you would only get a result of 45 (in most cases), if the alcohol from the three glasses is absorbed instantly into your system, which of course it isn’t. The safest amount of alcohol you can consume before driving is zero, but the reality is that the majority of motorists have an idea of how many drinks they can have before driving to remain under the limit. Hopefully, the information on this page will help you stay that little bit safer whilst still being your usual social-self!


Motoring Defence Solicitors are road traffic lawyers specialising in drink and drug driving offences. Based out of their central London offices, they provide free advice on a range of offences to motorists nationwide. You can contact Neil Sargeant for free on 0800 433 2880 or visit the website at

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