Inventory management of work tools at vehicle after sales service division PT. Arista Sukses Mandiri Jakarta still done manually using printed form (for dailycheck) and handwriting book (which record every tool that in and/or out from tool room), because of that staffs need more time to do them. Managing the tools inventory must be correct and precise both data and reality in the ground, but done manually the risk of data error is higher than if the staff do with computerized system. Beside that using computerized system in the scope of inventory of tools can make its process faster, so the time efficiency can be reached. Inventory system of tools based web is developed by the writer (also developer) to solve or at least reduce those problems. The method used in developing of this web based application is modified waterfall with whirlpools for the beginner as suggested by Powel, et al. This method consists of problem definition, requirement analytic, prototyping design, implementation, integration/testing, and release/maintenance. The final product of the research and development on this paper is web based application for work tools inventory management that can make the process of managing faster, more precise, and more efficiency.