We provide the first estimates of how pro-environmental consumers reduce their total carbon footprint using a carbon calculator that covers all financial transactions. We use data from Swedish users of a carbon calculator that includes weekly estimates of users' consumption-based carbon-equivalent emissions based on detailed financial statements, official registers, and self-reported lifestyle factors. The calculator is designed to induce behavioral change and gives users detailed information about their footprint. By using a robust difference-in-differences analysis with staggered adoption of the calculator, we estimate that users decrease their carbon footprint by around 10% in the first few weeks, but over the next few weeks, the reduction fades. Further analysis suggests that the carbon footprint reduction is driven by a combination of a shift from high- to low-emitting consumption categories and a temporary decrease in overall spending, and not by changes in any specific consumption category.