Gahshomar گاهشمار is a free educational app designed for Android users, allowing them to explore Iran's ancient calendrical systems. It features the Shahenshahi (Imperial) calendar, which dates back to the Achaemenid Empire, alongside the Solar Hijri and Gregorian calendar systems. Users can easily convert dates between these systems and delve into significant historical events and cultural celebrations from ancient Persia to modern times. The app provides a clean interface with dark and light modes, ensuring a user-friendly experience.

In addition to its calendar functionalities, Gahshomar offers educational content that highlights the Zoroastrian origins of Persian month names and their connections to the zodiac. With multilingual support in English and Persian, the app is fully localized and includes home screen widgets for quick access to dates. Gahshomar serves as an independent educational tool, presenting historical information based on scholarly sources for users interested in the rich heritage of Persian history.