Local governments who have signed the Covenant of Mayors have developed their Sustainable Energy and Climate Action Plans (SECAP). To reach these targets, local governments need to make sure they take the right actions. Hence, the EU City Calculator comes into play as it aims to help cities in their decision making and implementation of climate strategy by simulating climate scenarios. For example, city administrators and other stakeholders can analyse potential consequences of mitigation measures, such as how energy retrofitting of buildings can reduce carbon emissions and compare it with other measures.

As of April 2023, there are 24 measures available, each with several level of implementation, leading to a total of 70 possible combinations. Ten pilot cities are currently using the tool. Starting from late 2023, more cities will be able to use the tool after a training programme.