Hybrid buses offer the potential for fuel savings for transit operators and are expected to become important components of bus fleets around the world in the coming decade. This paper describes how a spreadsheet tool for a life-cycle cost (LCC) model for transit buses was developed to assist transit agencies in forecasting life-cycle operating and capital costs when choosing among various bus technologies, including hybrids. The tool is a key deliverable in a project sponsored by TCRP to assess hybrid electric bus performance in real-world operation. Forty hybrid electric buses were evaluated at four U.S. transit agencies, along with comparable conventional diesel and compressed natural gas buses. The LCC tool was created to cover key capital- and operating-cost factors that are based on the real-world data collected. The model is extremely flexible, and the user can override nearly all the data so that the model can be used in the future as costs and technologies change. This paper focuses on the model's structure, describes the case study buses, and illustrates an example of LCC calculation by using the model. More information about the project and its other results and deliverables can be found in TCRP Report 132.