Atnafu, Solomon (PhD)Nigussie, Zenebe2018-06-262023-11-292018-06-262023-11-292010-06http://etd.aau.edu.et/handle/123456789/3761In the growing world of technology, cellular devices have quickly emerged as one of the fastest evolving fields. They have increased greatly in both popularity and complexity, requiring more advanced operating systems and applications to meet the demands of the user. Android is a software stack designed to meet these demands in an open source environment. It includes an operating system, middleware, and key applications, as well as a Software Development Kit (SDK) for developers to create their own applications for the Android environment. This project is targeted to develop a perpetual Ethiopian and Gregorian calendar system and organizer application that runs on the top of Android mobile phones. Perpetual calendars provide a date over a wide range of years. This project came up with the Ethiopian calendar system with the corresponding Gregorian calendar of any year. The calendar provides the date of the public holidays of National (non religious), Christian and Muslim holidays of any month and year the user prefers to know. In addition to this users are supported to organize their tasks based on the Ethiopian calendar for a specific period of time with Ethiopic script. Once the task is organized or scheduled the users are alarmed when the time of the schedule reached. Besides these, users are supported to keep diaries at any specific date of Ethiopian calendar using Ethiopian scripts. Lastly the system has been tested and the result shows that it works correctly 100%. Keywords: Perpetual Ethiopian calendar, Ethiopian calendar, Ethiopian and Gregorian calendar, Ethiopic Organizer, Ethiopic Diary, Ethiopic Calendar on AndroidenPerpetual Ethiopian calendarEthiopian calendarEthiopian and Gregorian calendarEthiopic OrganizerEthiopic DiaryEthiopic Calendar on AndroidThesis