Bioventing is the process of aerating soils to stimulate in situ biological activity and promote bioremediation. Bioventing typically is applied in situ to the vadose zone and is applicable to any chemical that can be aerobically biodegraded, but to data bas been implemented primarily at petroleum-contaminated sites. Through the efforts of the U.S. Air Force Bioventing Initiative and the U.S. Environmental Protection Agency Bioremediation Field Initiative, bioventing has been implemented at more than 150 sites and has emerged as one of the most cost-effective and efficient technologies currently available for vadose zone remediation of petroleum-Battelle Memorial Institute prepared Principles and Practices of Bioventing (two volumes) for guidance to bioventing activities. During the preparation of Principles and Practices of Bioventing, an internally sponsored research and development project has been started at Battelle to build a Bioventing Design Tool to accompany the document. Microsoft Excel spreadsheet program was selected to build the BVDT. The capability of Excel's Visual Basic Applications is the primary reason of this choice. With many existing features and functions of Excel, we were able to construct tables and charts to collect field data and conduct data analyses. Considering the users who have minimal experience with the Excel program, we have built many macros, buttons, menus, charts, and functions to make the BVDT easier to use.