How definitions differ
The UK definition uses 10 ml or 8 g of pure alcohol per unit. A US standard drink uses 14 g. An Australian standard drink uses 10 g. A Canadian standard drink uses 13.45 g. Guidance about lower-risk consumption also differs, so check the current public-health advice for your country.
What the calculation uses
The calculator converts the serving to millilitres, applies the ABV, and uses 0.789 g per millilitre for the density of ethanol where a definition is expressed in grams. A pint, glass, can or bottle is not automatically one unit or standard drink.
What this result cannot tell you
A unit total cannot calculate your blood alcohol concentration, measure impairment or tell you whether it is safe or legal to drive. Alcohol can affect people differently. Read why an alcohol calculator cannot tell you if you can drive, and choose another journey home if you plan to drink.
Frequently asked questions
How do I calculate UK alcohol units?
Multiply the drink volume in millilitres by its ABV percentage, then divide by 1,000. For example, 500ml at 5% ABV contains 2.5 UK units.
Can an alcohol units calculator tell me if I can drive?
No. Alcohol units describe how much alcohol is in a serving. They do not measure blood alcohol concentration, impairment or whether you are safe or legal to drive.
How do I find the ABV?
Look on the can or bottle label. In a pub, bar or restaurant, ask staff if the strength or serving size is unclear.
Why does the exact serving size matter?
A 250ml glass contains twice the alcohol of a 125ml glass at the same strength. Large wine glasses, double spirits and stronger beers can make a simple drink count misleading.
Does the calculator save my drinks?
No. The running total stays only on this page and disappears when you refresh or close it. HeelClick records an anonymous completion event with the selected national definition, but not the serving details you enter.
Put the number inside a real plan
HeelClick keeps your drink limit beside your leave time, budget, way home and reason for tomorrow. It does not estimate blood alcohol concentration.
Make a plan with HeelClick