How many can I have before driving?

Drink driving and the legal alcohol limit in the UK

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 both from potential clients and our own friends and family. The truth is that it is a very difficult question to answer with any certainty. Every individual will process alcohol differently depending on their age, gender, height, weight and individual metabolism. You and your best pal could both drink 5 pints at the pub 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 OK to drive and actually being OK 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 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% accurate due to the number of variables involved. 

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 safe to drive. 

Below,  can see what your typical drinks contain in terms of alcohol units. Each unit roughly equates to 10µg of alcohol the legal limit is 35µg of alcohol per 100 millilitres of breath. The average person will metabolise 1 unit (10µg) alcohol each hour. 

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

So for example, the amount of alcohol in 3 small glasses of wine would place you over the limit as you would consume 4.5 units which equate roughly to 45µg 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 3 glasses is absorbed instantly into your system, which of course it isn’t (unless you’re somehow injecting the wine directly into your bloodstream which we definitely would not recommend!). 

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 above will help you stay that little bit safer whilst still being your usual social-self!

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