More than 3,000 churches are using a tool created by the Church of England to improve their carbon footprint.
The online tool aims to help parishes measure their carbon output and energy use and provides pointers to improve efficiency.
Churches are asked to provide information from their energy bills and the basic dimensions of their church buildings. The tool then reveals the church's carbon footprint, based on the lighting and heating usage and efficiency per person attending.
The Church of England hopes it will be used across its 40,000 buildings across England.
The Bishop of Salisbury, chair of the Church of England’s Environmental Working Group, said: "We cannot take meaningful action in response to the climate emergency threatening our planet until we understand our own carbon footprint.
"Tools such as the Energy Footprint Tool and collaboration between parishes, dioceses and the national church are vital to help us on this journey."
In February, General Synod committed the Church of England to a target of reaching net zero carbon emissions by 2030.
Dr Sam Nunney, from the Church of England’s research and statistics department, who helped to develop the carbon calculator, said: "We are thrilled by the response from parishes, many of whom have provided feedback and sent thanks for the ideas the tool presents to help improve energy efficiency.
"The reporting takes only ten minutes to complete and will prove to be a vital step to reach our church-wide net zero commitment."