To investigate the average self-reported size of a self-poured glass of wine for Australians aged 16 and over.Cross-sectional survey data were taken from the first wave of the Australian arm of the International Alcohol Control study administered to 2020 Australians aged 16 and over with an oversampling of heavy drinkers. Respondents were asked about their usual consumption in eight locations, with specific questions asked about drink type and how much they consumed. The 639 respondents who stated that they drank bottled wine purchased at off-licensed premises by the glass were asked 'How many glasses do you get to a bottle?'On average, small, generic-sized and large glasses were 144, 156 and 166 mL respectively, with an average glass size of 154 mL overall.Wine drinkers may be underestimating their own consumption due to large glass sizes, and survey data estimates of wine consumption should also be adjusted to account for glass size. The way a standard drink of wine is presented in health promotion materials should also be considered in light of these findings.