BEES Online is a next-generation application of the popular BEES (Building for Environmental and Economic Sustainability) tool. BEES implements a science-based approach for selecting cost-effective, environmentally-preferable building products. Developed by the NIST (National Institute of Standards and Technology) Engineering Laboratory, the tool is based on consensus standards and designed to be practical, flexible, and transparent. BEES Online, aimed at designers, builders, and product manufacturers, includes actual environmental and economic performance data for 230 building products. Now available as a free web-based application, the tool no longer requires a Windows operating system, making it accessible to the many designers who have requested versions of the tool for other computer platforms such as Macintosh. BEES Online runs strictly over the Internet, allowing instant access to the tool with no need for troublesome downloading and installation. The online platform also means NIST can readily add new building products to the BEES database as their data becomes available.