Stormwater ponds are among the most widely used tools for runoff detention and phosphorus removal, but many are now decades old and may be experiencing degraded performance from accumulated organic matter, phosphorus and aquatic vegetation. Monitoring pond performance through stormwater flow measurement is expensive and impractical at scale. Researchers developed a spreadsheet-based Pond Assessment Tool that uses readily available pond characteristics, water quality and spatial data to predict phosphorus concentration, sediment phosphate release and anoxia risk. The tool was built on water and sediment chemistry data from more than 35 ponds, enhanced by geospatial data, to develop risk indicators related to pond morphology, floating vegetation and sediment phosphorus pools. The tool, available at stormwater.safl.umn.edu/resources, is designed for practitioners to efficiently assess large numbers of ponds. Early versions have been well received by transportation, city, county and consulting staff. Future versions may address hydrologic functions, additional pollutants and the impacts of retrofits and design practices.