Aim: To examine young people’s main motive for pre-drinking in the United Kingdom, how much they drink on an event-specific night out, and whether motives or socioeconomic status (particularly their income level) explain the alcohol quantities they drink. Methods: Multilevel logit and poisson models were used on a survey of 628 people (aged 18-35) conducted on-site in 26 bars, clubs and pubs in four cities and towns. Results: Young males drink on average 9.8 and females 7.4 standard units of alcohol before a night out. Saving money is the most prevalent motive for pre-drinking. Although lower income levels cannot explain whether a young person will pre-drink on an event-specific night out, young people’s income level and their motives explain the quantities they consume. Lower-earning males who pre-drank to save money consumed larger quantities of alcohol at home and lower-earning females also pre-drank larger quantities either because they wanted to get out of control or because they wanted to be social. Conclusions: Prevention strategies likely to be effective in reducing the alcohol quantities that young people pre-drink should take into account both socioeconomic status and motives for pre-drinking.