Using a generalization of the Becker's time allocation model to estimate the shadow price of time, the article proposes to evaluate the component of home production which could be substituted by market goods and services. An enlarged households' total expenditure including the production of the informal sector and the value of domestic production and the corresponding enlarged GDP are compared to their monetary counterparts in five developed and underdeveloped countries. Domestic production substituable to market goods corresponds to 23 to 41% of the GDP in Canada, France, Poland and the US, but much less in Burkina Faso because of much lower opportunity cost of time and elasticities of substitution. Finally, the enlarged GDP including the informal sector is larger by 40% than the official GDP in the three developed countries, 34% in Poland and by 54% in Burkina Faso.