Universal Chronology Atlas

One date. Every system.

Explore a date across Gregorian and regional calendars, historical chronologies, astronomy, cultural traditions, and clearly labelled fictional dating systems.

Calendar and chronology explorer

Compare civil, religious, traditional, reconstructed, and historical calendars. Review continuous day counts, era systems, ISO week and ordinal dates, Julian dates, and computing epochs.

Astronomy at a precise UTC instant

Inspect calculated Moon, Sun, planet, season, and sidereal-time data. Date-only calculations use 12:00 UTC; optional observer input accepts latitude and longitude coordinates.

English and Arabic

The Atlas supports English, Arabic, right-to-left layout, light and dark themes, keyboard navigation, and responsive screens.