This report responds to a request from COP 24 to prepare, regularly update and publish before each session of the subsidiary bodies brief reports on standard costs and, if available, options for reducing the cost of activities where practicable. As this is the first report in response to this request, it includes an overview of standard costing practices in other parts of the United Nations system, as well as some options for different approaches to preparing and using standard costs for supporting decision-making in relation to new UNFCCC mandates under consideration by the governing or subsidiary bodies.