The Bangladesh Erosion Monitor (BEM), developed through the Google Earth Engine platform using JavaScript, is a novel tool designed to assess erosion and accretion in Bangladesh’s major river systems. Utilizing the extensive historical records of the Joint Research Centre (JRC), this approach conducts a comprehensive planform change analysis. It intricately blends data covering administrative boundaries, essential infrastructures, the dynamics of water flow, and patterns of global land use. This integration offers a multi-faceted perspective on how river systems evolve and interact with both the natural environment and human-developed landscapes. This approach aids in understanding erosion impacts and supports informed decision-making. Including actionable information for policymakers, the tool identifies vulnerable infrastructure like embankments and ferry terminals, estimates potential damages to agriculture and households from river erosion, and can perform a scenario analysis to calculate inundation depths in breached coastal polders. Its multifaceted data layers enable users to predict and strategize against the adverse effects of riverbank erosion and flooding. Validated against real-time riverbank survey data, this tool represents an advancement in the field of environmental risk management by effectively implementing geospatial technology in novel new ways. It provides valuable insights for policy development, especially in addressing river erosion and flood hazards in Bangladesh, thus contributing meaningfully to the field.