First things first…
Let’s make one thing absolutely clear at the outset - this calculator is not intended to help you work out how much you can drink on a night out before driving home.
If you are drinking any amount of alcohol on a night out - even one drink - you should leave the car at home and make alternative arrangements.
And the calculator won’t help you if you are arrested for drink driving.
What it will do is enable you to calculate roughly when it will be safe for you to drive the morning after drinking alcohol. And it can help you calculate when to stop drinking alcohol if you have to drive the following morning.
How the 'Morning After Calculator' works
The calculator allows one hour for each unit of alcohol, plus an additional hour for the first drink to allow for the alcohol to enter the bloodstream. It then rounds up the calculation to the nearest half hour.
The calculator bases its calculation from the time you stop, not when you start drinking. Some people say this is over-cautious, but we’d rather be safe than sorry.
The 'hours before driving' calculation is not based on any drink drive limit - it is the length of time when the alcohol in the drinks you've consumed is likely to have passed through your body. This is when we suggest you will be 'safe to drive'.
How to use the calculator
Simply tot up the drinks you consumed the night before - or better still, use the calculator smartphone app to keep track of what you’re drinking while you’re out - and the calculator will store them and give you a rough calculation of when you will be safe to drive.
We’ve included a fair number of drinks, but if you can’t find the exact drink you consumed there may be something of similar alcoholic content (ABV).