Estate renewal has come to be touted as a means of improving social housing supply both qualitatively and quantitatively, replacing ageing and under-maintained dwellings and increasing the total stock of social housing. In this paper, we examine the latter claim. We develop novel measures and methods for calculating the social housing supply impacts of estate renewal, taking account of the reduction in supply caused by tenant relocations and dwelling demolitions prior to the delivery of new social housing. Using administrative data on tenant relocations and dwelling completions for three projects in Sydney, we calculate the social housing accommodation deficit caused by the renewal process, subsequently, the time required for each project to deliver more nights of accommodation than this deficit. These measures illuminate the significant impacts of estate renewal on the social housing system and problematize its justification based on gross or net social housing supply. They constitute a valuable method for examining estate renewal, wherever it may occur.