Protocol
Count the actual alcohol, not just the number of glasses
One glass is a container, not a fixed quantity of alcohol.
When it fits
- You want an accurate account of alcohol consumed.
When to avoid it
- Do not use this calculation to decide when driving is safe. If you may be physically dependent, stopping suddenly can be dangerous; seek medical support rather than attempting an unsupported detox.
Why it matters
Read the volume and alcohol by volume together. Under the UK convention, units equal millilitres multiplied by ABV percentage and divided by 1,000. Keep the convention explicit: a standard drink in another country may represent a different quantity.
Steps
- Record the actual volume and labelled strength, including refills.
- Use one named unit convention consistently.
- Discuss concerns or difficulty cutting down with an appropriate healthcare service.
An example
A hypothetical 500 ml drink at 5% ABV contains 2.5 UK units. Counting it merely as one drink hides that quantity.
Check your result
The record describes volume, strength and unit convention without turning the result into a safe allowance.
Keep this limit in mind
- Do not use this calculation to decide when driving is safe. If you may be physically dependent, stopping suddenly can be dangerous; seek medical support rather than attempting an unsupported detox.
Connected ideas
Useful withAdd professional support to a quit-smoking attempt
Evidence and sources
In the UK convention, alcohol units are calculated as volume in millilitres multiplied by ABV percentage and divided by 1,000.
This quantifies alcohol using one convention; it is not a safe allowance or a driving-clearance calculation.
Calculating alcohol units · Calculating units
NHS warns that suddenly stopping alcohol can be harmful for someone who is physically dependent and advises professional support.
Dependence and withdrawal risk require clinical judgment; this card provides no home detoxification plan.
Alcohol support · Stopping drinking and physical dependence