Objective:Alcohol consumption may be wrongly estimated because of inaccurateinformation on actual portion sizes. We compared portion sizes of wine, fortifiedwine and straight spirits poured at home with the Dutch standard drink sizes.Design:Participants measured portion sizes of wine, fortified wine and straightspirits at home up to a maximum of three times and reported these via an onlinesurvey. Average portion sizes (in millilitres) were compared with the Dutchstandard drink sizes. Portion sizes were compared between subgroups of gender,age, BMI and level of education, and for different glass types.Setting:Wageningen and surroundings, the Netherlands.Participants:Adults (N201) living in the Netherlands and consuming wine and/orstraight spirits at home at least once per week.Results:Participants poured on average 129·4 ml white wine and 131·7 ml redwine, which is significantly more than the standard of 100 ml. For fortified wine,the average poured amount was 94·0 ml, significantly more than the standard of50 ml; also for straight spirits the poured amount was significantly more than thestandard (47·0v. 35 ml).Conclusions:Participants’portion sizes of wine, fortified wine and straight spiritspoured at home were on average larger than the Dutch standard drink sizes. Thissuggests that at-home alcohol consumption in the Netherlands is underestimated.