Building on the notion of the ‘social nature’ of money, this article investigates how dual-earner couples in Germany, Spain, Sweden and the US handle money in their everyday lives. We analysed in-depth, open-ended interviews conducted with 45 couples in these four countries to determine whether they define money as ‘joint’ or ‘separate’ and to investigate the consequences such definitions have for couple relationships. The concept of the convertibility of money helped us to spell out these consequences in detail. In addition, we explore whether the meaning of ‘joint’ or ‘separate’ money might relate to institutionalized cultural frameworks embodied in welfare policies that vary between countries. Couples in Spain and in Sweden seem to practise a low degree of convertibility of money into other resources, but they do so for different reasons: in Spain, money tends to be considered ‘joint money’ from the outset, whereas in Sweden it is often kept ‘separate’ and outside the relationship. In contrast, in the US and Germany, money, while often classified as ‘joint’ by the couples, is more likely to be seen as each partner’s individual contribution to the relationship. Thus it can be, and often is, converted into resources such as domestic work or recognition.