In South Africa one unit of alcohol is accepted as about 10ml of 100% pure alcohol. Such a unit of alcohol is equivalent to 0.02 grams of alcohol per 100ml of blood. Contrary to popular belief one drink is not equivalent to one unit of alcohol.
| Drink | Volume | % of Alcohol in Drink | Units of Alcohol |
| Can of lager or cider | 500ml | 4% | 2 units |
| Glass of wine | 175ml | 14% | 2.5 units |
| Spirit and Mixer | 25ml | 40% | 1 units |
| Alcopop (flavoured alcohol drinks) | 400ml | 5% | 2 units |
| Cocktail (5 different alcoholic components | 125ml | 40% | 5 units |
