The 2030 Agenda and Paris Agreement tied the knot between sustainable economic development and a climate-resilient, low greenhouse gas (GHG) emissions future. Moving forward, accounting for potential changes in GHG emissions will be a vital component of any agricultural investment, project, or policy proposal under consideration by any country, institution, or organization. To support the international community’s efforts with quantifying changes in GHG emissions, the Food and Agriculture Organization of the United Nations (FAO) developed the Ex-Ante Carbon-balance Tool (EX-ACT). Based on the Intergovernmental Panel on Climate Change (IPCC) methodology, EX-ACT provides its users a consistent way of estimating and tracking the impact of agricultural, forestry, and other land-use (AFOLU) investments and policies on GHG emission levels. EX-ACT is a free, open-source, Excel-based model and is available in all UN languages, as well as Bahasa, Vietnamese, Portuguese, and German.