Many people enjoy a glass of wine or beer with dinner or a casual drink with friends. We also want to drink at a level, which is not bad for our health, and not drive home if we might be over the limit.

People metabolize alcohol at differing rates. Many things affect it. These include weight, gender, whether you eat whilst drinking, how regularly we drink and how quickly we drink.

This calculator lets you work out an approximate blood alcohol concentration based on your weight, gender, number of drinks consumed and the number of drinks you have had in the time since you started drinking today.

It is of course not the same as blowing onto a bag or having a blood reading and cannot take all of your factors into account. Nevertheless it will give you a guide to where you are as well as an estimate of how long it will take for your blood alcohol reading to reach zero.