We provide a blueprint for constructing measures of state capacity in premodern states, offering several advantages over the current state of the art. We argue that assessing changing state capacity requires considering the composition of revenues, expenditure patterns, and local-level budgets. As an application, we examine the case of Portugal (1367–1844). Our findings demonstrate that throughout most of this extended period, Portugal maintained comparatively high fiscal and legal capacities. This challenges claims that Portugal’s economic decline from the second half of the eighteenth century was due to low state capacity.