It’s sometimes difficult to know whether you’re legal to drive. You’ve just had one glass of champagne at a friend’s wedding or you had a few pints last night – can you drive this morning?
Using our alcohol calculator takes the guesswork out of the question “How long before I can drive?”
And it will warn you if you’re getting close to – or over – the limit.
The penalties for drink driving are very severe – using a drink drive calculator could make the difference between having a clean driving licence, and being disqualified from driving. Let us guide you through everything you need to know before hitting the road!
Table of Contents
What’s the UK drink-drive limit?
We show the drink drive limits for the UK in the table below. The limit is different depending on whether you’re in Scotland or the rest of the UK.
|Area||per 100ml blood||per 100ml breath||per 100 ml urine|
|England, Wales, NI||80mg||107mg||35 micrograms|
The alcohol limit for the UK can be expressed in terms of alcohol in the blood, breath or urine. These are the three different ways you may be asked to provide a sample – via a breathalyser at the side of the road, or through a blood or urine sample given at a police station.
Driving after drinking carries very high penalties if you’re over the limit. That’s why we recommend you use an alcohol/driving limit calculator to check whether you’re okay to drive, and an alcohol absorption rate calculator to see how long it will take you to sober up. (Think of them as a drunk calculator and a sober calculator, if you like.)
Of course, no calculator is a hundred percent reliable. An alcohol calculator for driving next day will make assumptions about how quickly your body processes alcohol, but you might be someone whose body doesn’t do this very fast. It’s best to be conservative and to add a little extra time. If you want to know how much alcohol is too much, the calculator might show you’re right up against the limit – it might be best to let someone else do the driving and pick your car up tomorrow.
Remember the limits for England and Wales and for Scotland are different! A drink drive calculator for Scotland will stop you driving well before the rest-of-UK one does. Make sure you’re not using the alcohol calculator UK if you’re north of the border.
How much can I drink and still be able to drive?
There is no hard and fast limit for how much you can drink and still be legal to drive, because everyone’s body processes alcohol differently, but our alcohol calculator for driving gives you an estimate.
The reason that it’s difficult to give a precise figure is that everyone is different. Your ability to process alcohol depends on a number of factors:
- whether you’re male or female,
- your metabolism,
- whether you ate food with your drink,
- whether you’re feeling stressed,
- how much you weigh,
- how quickly you drink,
- whether you smoke,
- your age,
- any medication you take.
So even a good alcohol dilution calculator, which takes factors like your gender and weight into account, will only give you a rough idea of how much you can drink without the breathalyser test giving you a red card. An “Am I over the limit to drive?” calculator can help you make informed decisions, but remember it can’t guarantee that you’re legal.
It’s best not to drink anything. Even while you’re still well below the limit, drink can slow your reflexes and make you underestimate your speed.
And it is worth knowing that if you’re clearly not able to drive properly, even if you pass a breathalyser test you can still be found guilty of drink driving. (The offence is “driving while unfit through drink”.)
How many units to drive and still be legal?
The 80mg limit for alcohol means that men can drink up to 4 units and women up to 3 units of alcohol before reaching the limit. (Remember that in Scotland, the limit’s lower, at 50mg.)
Just one pint of strong cider at 8% would put you over the limit. Many people would probably be getting close to the limit on just one pint of best bitter at 4.8%.
One unit of alcohol is what the average body can process in an hour, and is equal to 10ml of alcohol. So even one point of low strength beer at 2.5% will take 1 1/2 hours to be eradicated from your bloodstream completely.
How many units are in a pint of beer or cider?
The table below shows the number of units in a pint for drinks at varying strengths.
A pint of low alcohol beer at 2.5%, for instance, has 1.4 units; a strong stout or lager at 6% would deliver 3.4 units of alcohol.
|Alcohol by Volume (ABV)||Pint|
An alcohol unit calculator can tell you exactly how many units there are in a given pint of beer or cider; it depends on the strength of the drink expressed in the percentage ABV (alcohol by volume), which will be shown on the pump clip or bottle label. If you’re using a unit of alcohol calculator you do need to look at the alcohol content of what you’re drinking.
At least ABV markings make the job easy. Any homebrewer can tell you that using a specific gravity alcohol calculator to find out how much alcohol is in a given brew is no fun at all.
How many units are there in a bottle of wine?
A 750ml bottle of wine at 13.5% alcohol contains 10 units of alcohol. So half a bottle of wine would put you definitely over the limit.
If you want to know how many units in a glass of wine you need to know the size of the glass as well as the strength of the wine. For instance, a 125ml glass at 12% would contain 1.5 units. You could have that with a meal and stay legal to drive.
But many bars and restaurants serve wine in bigger 175ml glasses. One of those, again with wine at 12%, would contain 2.1 units. And the big 250ml wine glasses that have become very popular in bars contain 3 units of alcohol, which is getting very close to the limit for most women.
How many units are there in spirits?
Let’s find out how many units of alcohol will you find in a glass of spirit.
|% alcohol||units in a single 25ml shot|
|40 – gin||1|
|46% – chill filtered whisky||1.15|
|70% – cask strength whisky||1.75|
Most spirits commonly served in UK pubs are around 40%. However, if you’re drinking single malts or other spirits at home, watch out for increased alcohol levels and use a drink calculator if your drinks are of different strengths.
Remember that this isn’t a “how much alcohol to get drunk” calculator. You could be well over the legal limit for driving, and not be drunk. The fact that you can still walk in a straight line and you’re not slurring your words (or picking a fight, or crying in the toilets) doesn’t mean that you’re okay to drive.
How many drinks is the legal limit?
The answer is probably fewer than you think.
For the average man, the legal limit could be:
- two pints of 3.5% bitter;
- one pint of Stella Artois;
- a single large glass of Rioja red wine;
- two double shots of whisky at 40% alcohol;
- two bottles of 5.5% alcopop.
For the average woman, it’s even less. One double gin and tonic might leave you legal to drive, but two will almost certainly put you over the limit.
These figures are based on averages, but if you want to know how many drinks would get you to the limit, you’ll want to use an alcohol calculator for driving. Rather than being based on the ‘average’ person, a calculator it uses other factors as well to work out the likely total for you personally.
If you’re heading out with friends for the evening, it’s worth knowing that some pubs and many beer festivals and other events now offer free soft drinks for designated drivers.
How long after drinking can I drive?
Use the morning after calculator to see whether you’re legal yet. And just be sure, you probably should wait a little bit longer…
It’s important to realise just how long it can take to work (or sleep) off the effects of alcohol. If you’re out for a few drinks and get home at midnight, you might not actually be legal to drive till late in the afternoon.
How long does it take for alcohol to leave your system? On average, every unit of alcohol takes an hour to process. So if you’ve had three pints of bitter, that’s six units and it would take six hours for you to be fully sober. However, after three hours you should be down to the legal limit for driving.
If you have, let’s say, six alcopops over the course of an evening, that’s twelve units – twelve whole hours to fully process the booze, and at least eight before you’re legal. Get to bed at two in the morning, and you’ll want to wait till at least 10am before you even think about getting behind the wheel.
The process can’t be accelerated. Whatever you’ve heard, drinking more water won’t make you legal quicker – though it might stop you getting a hangover. Drinking coffee won’t work either. So if you want to go out for a few drinks in the evening, don’t plan on driving first thing in the morning.
If you’re asking “When will I be sober?” then using a safe-to-drive calculator is going to give you a more reliable estimate than guessing.
What’s the penalty for drinking and driving?
Drink driving penalties are very, very tough. You could get six months in prison, an unlimited fine, and at least a year’s driving ban.
A second conviction within ten years of the first will get you banned for three years.
It’s worth noting that drink driving is a serious criminal conviction, unlike – say – speeding or failing to stop for a red light. It will go on your criminal record, and that could mean you’ll have difficulties travelling abroad, or looking for employment.
How drink driving convictions may affect your car insurance quote?
Insurers take a very dim view of drink driving and will certainly increase your premiums. It may be difficult to find a company prepared to insure you, so you may have to consider specialist insurers.
Drivers convicted of drink driving could see their insurance premiums as much as double. Younger drivers will be particularly badly affected as insurers already consider them a high risk even without a motoring conviction.
Get to know more about driving offences and how they could affect your car insurance here.
How long do I have to declare drink driving to insurance?
The points from a drink driving offence will remain on your licence for 11 years and you’ll need to tell insurers about them during that period.
However, there is a little ambiguity in the law here. DR10 (drink driving) convictions are regarded as ‘spent’ after 5 years. Insurers are not supposed to ask about spent convictions. Using an insurer which specialists in convicted driver insurance, you may not be asked to disclose spent convictions. This could get you a better quote.
If you are asked directly whether you have points on your licence, though, you must tell the truth. Failing to disclose the information could invalidate your insurance.
How much is car insurance after drink driving ban?
Your car insurance will probably double after a drink driving ban.
You’ll also find that many high volume, big name insurers won’t want to insure you, so you will have a limited choice of insurers. Less choice means less competition – and less competition means more expensive premiums and less room for you to negotiate a reduction.
Don’t want to pay double? Get in the habit of using a blood alcohol level calculator to ensure you know whether you’re legal to drive.
Is car insurance void when drink driving?
Many insurance policies state that your insurance is invalidated if you drink and drive. Check your policy details.
That could mean, if you have an accident, that the insurer won’t pay out for any damage to your car. It may also mean your insurer taking legal action against you to reclaim any payout it has had to make to a third party.
For instance, if you totalled someone’s Ferrari Testarossa by hitting it while it was parked, your insurer might want to recover the whole £100,000 cost from your bank account.
That’s even more expensive than the increase in your premiums once you’ve served your disqualification period. And it would be really galling if you could have saved yourself the trouble by using a “how much can I drink and drive” calculator to check that you were still legal.