Understanding future greenhouse gas (GHG) emissions trajectories is crucial for addressing global climate change. Climate Watch is an online data platform that tracks global and country GHG emissions, as well as climate commitments. This technical note describes a methodology used by Climate Watch for estimating future global and country-level GHG emissions based on GHG targets communicated in countries’ Nationally Determined Contributions (NDCs). It aims to estimate countries’ economy-wide GHG emissions for target years, assuming NDC targets are fully achieved. For sectors and GHGs not covered by NDCs, supplemental data sources are used. Global GHG emissions are aggregated from country-level estimates, accounting for emissions not covered by NDCs, such as international bunkers. This analysis supports the understanding of NDCs, the tracking of progress towards national and global climate goals, and helps to identify gaps in global emissions pathways. The methodology underpins data and visualizations made available through Climate Watch’s NDC Tracker.