This research aims (1) to develop a web application for elder care center management capable of handling work schedules, time management, and internal financial data in a way that allows for easy tracking and use, using a software engineering process based on the waterfall model, implemented with TypeScript and JavaScript using Angular for the frontend and Node.js with Prisma ORM connected to a PostgreSQL database for the backend to ensure efficient system performance, and (2) to study the effectiveness of the system, using a web-based elderly care management application evaluated by three purposively selected experts. The results showed that (1) the system enables elderly care centers to manage information in an organized manner, reducing staff workload and improving operational convenience and efficiency, meeting the specified requirements, and (2) the expert evaluation of the system’s effectiveness rated it at a “high” with an average score of  = 4.43 and a standard deviation (S.D.) = 0.65, indicating that the system meets user needs in terms of usability and enhances service efficiency through effective management of medical records, equipment, supplies, and activity schedules.